{"id":152562,"date":"2014-02-13T15:13:26","date_gmt":"2014-02-13T20:13:26","guid":{"rendered":"\/gazette\/?p=152562"},"modified":"2019-03-19T16:53:39","modified_gmt":"2019-03-19T20:53:39","slug":"evolution-in-real-time","status":"publish","type":"post","link":"https:\/\/news.harvard.edu\/gazette\/story\/2014\/02\/evolution-in-real-time\/","title":{"rendered":"Evolution in real time"},"content":{"rendered":"\n\t
\"\"

Since 1988, Richard Lenski has watched E. coli bacteria multiply through 59,000 generations, a span that has allowed him to observe evolution in real time. He also found that one of the 12 bacterial lines he has maintained has developed into what he believes is a new species.<\/p>

Photo by Melanie Rieders<\/p><\/figcaption><\/figure>\n\n\t

\n\t\t\t\n\t\t\tHealth\t\t<\/a>\n\t\t\n\t\t

\n\t\tEvolution in real time\t<\/h1>\n\n\t\n\t\t\t<\/div>\n\t\t\n\t
\n\t\t
\n\t\t\t
\n\t\t\t\t\t

\n\t\tAlvin Powell\t<\/p>\n\t\t\t

\n\t\t\tHarvard Staff Writer\t\t<\/p>\n\t\t\t\t\t<\/address>\n\t\t<\/div>\n\n\t\t

\n\t\t\t59,000 generations of bacteria, plus freezer, yield startling results\t\t<\/h2>\n\t\t\n<\/header>\n\n\n\n
\n\n\n\t\t

After 26 years of workdays spent watching bacteria multiply, Richard Lenski<\/a> has learned a thing or two.<\/p>\n

He\u2019s learned that naturalist Charles Darwin was wrong about some things. For one, evolution doesn\u2019t always occur in steps so slow and steady that changes can\u2019t be observed.<\/p>\n

Lenski also learned that a laboratory freezer can function as a time machine.<\/p>\n

A professor at Michigan State University<\/a>, Lenski has watched E. coli<\/i> bacteria multiply through 59,000 generations, a span that has allowed him to observe evolution in real time. Since his Long-Term Experimental Evolution Project<\/a> began in 1988, the bacteria have doubled in size, begun to mutate more quickly, and become more efficient at using the glucose in the solution where they\u2019re grown.<\/p>\n

More strikingly, however, he found that one of the 12 bacterial lines he has maintained has developed into what he believes is a new species, able to use a compound in the solution called citrate \u2014 a derivative of citric acid, like that found in some fruit \u2014 for food.<\/p>\n

Lenski described his groundbreaking work at Harvard\u2019s Mineralogical and Geological Museum on Wednesday during a talk sponsored by the Harvard Museum of Natural History<\/a>, one of the Harvard Museums of Science & Culture<\/a> (HMSC).<\/p>\n

His presentation, \u201cTime Travel in Experimental Evolution,\u201d was introduced by HMSC executive director Jane Pickering<\/a> and by Jonathan Losos, the Monique and Philip Lehner Professor for the Study of Latin America and curator of herpetology in the Museum of Comparative Zoology<\/a>.<\/p>\n

Losos, who studies the behavior and evolution of Anolis lizards on Caribbean islands, called Lenski\u2019s long-running work \u201csimply extraordinary\u201d and said that his approach has been adopted by other researchers around the world.<\/p>\n

Losos said Lenski\u2019s talk was particularly appropriate because it occurred on the 205th anniversary of Darwin\u2019s birth. In the spirit of the ongoing Olympics, Losos said that if there were ever an all-star team of evolutionary biologists, Lenski would be its captain.<\/p>\n

While the ability to observe creatures with short reproductive times over thousands of generations has brought insights, Lenski said it was the use of the laboratory freezer that allowed the work to cross from observation into experimentation.<\/p>\n

Researchers periodically froze samples of E. coli, <\/i>and because the frozen bacteria remained viable, scientists interested in particular evolutionary developments could directly compare modern populations against their ancestors. In addition, the development of cheap, accurate ways to analyze the genome has given researchers better analytical tools.<\/p>\n

One of the central questions Lenski has explored is the tension between evolution\u2019s opposing forces: the random mutations that initiate genetic change and the natural selection that shapes which mutations survive. Those forces, Lenski said, provide evolutionary pressure in different directions.<\/p>\n

Random genetic mutation pushes organisms to diversify, while natural selection is a homogenizing force, favoring characteristics that enhance survival under specific conditions.<\/p>\n

The experiment has run according to the same protocol since it began. E. coli <\/i>bacteria are grown in the solution of glucose, a kind of sugar. The glucose is carefully measured so it eventually runs out and creates a period of scarcity and starvation before the bacteria are propagated the next day and transferred into a fresh solution. Every 75 days, roughly 500 generations, a portion of the cultures is frozen.<\/p>\n

Though the bacteria were originally genetically identical, they have evolved. Today\u2019s populations grow roughly 80 percent faster than the original lines, a development that Lenski called \u201ca beautiful example of adaptation by natural selection.\u201d<\/p>\n

An analysis of the 12 lines after 20,000 generations showed 45 mutations from the ancestral population among the bacteria\u2019s roughly 4,000 genes. Many of the same genes were mutated in all lines, but it was rarely exactly the same mutation within the genes, Lenski said. He equated the bacteria\u2019s evolutionary feats in the glucose-limited \u201cflask world\u201d with those of mountain climbers finding other routes to the peak.<\/p>\n

\u201cPopulations are climbing Mount Glucose in similar, though not identical, ways,\u201d Lenski said.<\/p>\n

After 30,000 generations, researchers noticed something strange. One population had evolved the ability to use a different carbon-based molecule in the solution, called citrate, as a power source.<\/p>\n

Researchers wondered whether it was the result of a rare, single mutation, or a more complex change involving a series of mutations over generations. To find out, one of Lenski\u2019s postdocs, Zachary Blount, took some of the frozen cells and grew them in a culture lacking glucose, with citrate as the only potential food source.<\/p>\n

After testing 10 trillion ancestral cells from early generations, he got no growth. But when he tested cells from the 20,000th generation on, he began to get results, eventually finding 19 mutants that could use citrate as a power source. The results showed that the citrate-eating mutation was most likely not the result of a single mutation, but one enabled by multiple changes over 20,000 generations.<\/p>\n

In further testing to determine if the new bacteria were different enough to qualify as a new species, Lenski\u2019s researchers found that beyond changes to the genes responsible for glucose and citrate consumption, other changes had occurred in the organism that had made it less fit to survive in a glucose-only environment,<\/p>\n

\u201cWe find they are getting less fit in the ancestral niche over time,\u201d Lenski said. \u201cI would argue that citrate users are \u2014 or are becoming \u2014 a new species.\u201d<\/p>\n

Lenski said he\u2019d like to see the experiment continue in the future, even after he has retired, because the bacteria continue to surprise.<\/p>\n

\u201cI call this the experiment that keeps on giving, because the bacteria continue to do interesting things,\u201d Lenski said. \u201cI\u2019d like this experiment to continue long after I\u2019m gone.\u201d<\/p>\n\n\n<\/div>\n\n\t\t","protected":false},"excerpt":{"rendered":"

After 26 years of workdays spent watching bacteria multiply, Richard Lenski has learned that evolution doesn\u2019t always occur in steps so slow and steady that change can\u2019t be observed. <\/p>\n","protected":false},"author":105622744,"featured_media":152564,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"gz_ga_pageviews":259,"gz_ga_lastupdated":"2024-05-16 03:05","document_color_palette":"crimson","author":"Alvin Powell","affiliation":"Harvard Staff Writer","_category_override":"","_yoast_wpseo_primary_category":"","_jetpack_memberships_contains_paid_content":false,"footnotes":""},"categories":[39644],"tags":[3753,9949,11550,12776,15954,15957,18822,19837,22000,23989,24744,25200,25571,29387],"gazette-formats":[],"series":[],"class_list":["post-152562","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-health","tag-alvin-powell","tag-darwin","tag-e-coli","tag-evolution","tag-harvard-museum-of-natural-history","tag-harvard-museums-of-science-culture","tag-jane-pickering","tag-jonathan-losos","tag-long-term-experimental-evolution-project","tag-michigan-state-university","tag-mutation","tag-natural-selection","tag-news-hub","tag-richard-lenski"],"yoast_head":"\nEvolution in real time — Harvard Gazette<\/title>\n<meta name=\"description\" content=\"After 26 years of workdays spent watching bacteria multiply, Richard Lenski has learned that evolution doesn\u2019t always occur in steps so slow and steady that change can\u2019t be observed.\" \/>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/news.harvard.edu\/gazette\/story\/2014\/02\/evolution-in-real-time\/\" \/>\n<meta property=\"og:locale\" content=\"en_US\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"Evolution in real time — Harvard Gazette\" \/>\n<meta property=\"og:description\" content=\"After 26 years of workdays spent watching bacteria multiply, Richard Lenski has learned that evolution doesn\u2019t always occur in steps so slow and steady that change can\u2019t be observed.\" \/>\n<meta property=\"og:url\" content=\"https:\/\/news.harvard.edu\/gazette\/story\/2014\/02\/evolution-in-real-time\/\" \/>\n<meta property=\"og:site_name\" content=\"Harvard Gazette\" \/>\n<meta property=\"article:published_time\" content=\"2014-02-13T20:13:26+00:00\" \/>\n<meta property=\"article:modified_time\" content=\"2019-03-19T20:53:39+00:00\" \/>\n<meta property=\"og:image\" content=\"https:\/\/news.harvard.edu\/gazette\/wp-content\/uploads\/2014\/02\/021214_evolve_005-jpeg_605.jpg\" \/>\n\t<meta property=\"og:image:width\" content=\"605\" \/>\n\t<meta property=\"og:image:height\" content=\"403\" \/>\n\t<meta property=\"og:image:type\" content=\"image\/jpeg\" \/>\n<meta name=\"author\" content=\"harvardgazette\" \/>\n<meta name=\"twitter:card\" content=\"summary_large_image\" \/>\n<script type=\"application\/ld+json\" class=\"yoast-schema-graph\">{\"@context\":\"https:\/\/schema.org\",\"@graph\":[{\"@type\":\"Article\",\"@id\":\"https:\/\/news.harvard.edu\/gazette\/story\/2014\/02\/evolution-in-real-time\/#article\",\"isPartOf\":{\"@id\":\"https:\/\/news.harvard.edu\/gazette\/story\/2014\/02\/evolution-in-real-time\/\"},\"author\":{\"name\":\"harvardgazette\",\"@id\":\"https:\/\/news.harvard.edu\/gazette\/#\/schema\/person\/78d028cf624923e92682268709ffbc4b\"},\"headline\":\"Evolution in real time\",\"datePublished\":\"2014-02-13T20:13:26+00:00\",\"dateModified\":\"2019-03-19T20:53:39+00:00\",\"mainEntityOfPage\":{\"@id\":\"https:\/\/news.harvard.edu\/gazette\/story\/2014\/02\/evolution-in-real-time\/\"},\"wordCount\":985,\"publisher\":{\"@id\":\"https:\/\/news.harvard.edu\/gazette\/#organization\"},\"image\":{\"@id\":\"https:\/\/news.harvard.edu\/gazette\/story\/2014\/02\/evolution-in-real-time\/#primaryimage\"},\"thumbnailUrl\":\"https:\/\/news.harvard.edu\/wp-content\/uploads\/2014\/02\/021214_evolve_005-jpeg_605.jpg\",\"keywords\":[\"Alvin Powell\",\"Darwin\",\"E. coli\",\"Evolution\",\"Harvard Museum of Natural History\",\"Harvard Museums of Science & Culture\",\"Jane Pickering\",\"Jonathan Losos\",\"Long-Term Experimental Evolution Project\",\"Michigan State University\",\"Mutation\",\"natural selection\",\"News Hub\",\"Richard Lenski\"],\"articleSection\":[\"Health\"],\"inLanguage\":\"en-US\",\"copyrightYear\":\"2014\",\"copyrightHolder\":{\"@id\":\"https:\/\/news.harvard.edu\/gazette\/#organization\"}},{\"@type\":\"WebPage\",\"@id\":\"https:\/\/news.harvard.edu\/gazette\/story\/2014\/02\/evolution-in-real-time\/\",\"url\":\"https:\/\/news.harvard.edu\/gazette\/story\/2014\/02\/evolution-in-real-time\/\",\"name\":\"Evolution in real time — Harvard Gazette\",\"isPartOf\":{\"@id\":\"https:\/\/news.harvard.edu\/gazette\/#website\"},\"primaryImageOfPage\":{\"@id\":\"https:\/\/news.harvard.edu\/gazette\/story\/2014\/02\/evolution-in-real-time\/#primaryimage\"},\"image\":{\"@id\":\"https:\/\/news.harvard.edu\/gazette\/story\/2014\/02\/evolution-in-real-time\/#primaryimage\"},\"thumbnailUrl\":\"https:\/\/news.harvard.edu\/wp-content\/uploads\/2014\/02\/021214_evolve_005-jpeg_605.jpg\",\"datePublished\":\"2014-02-13T20:13:26+00:00\",\"dateModified\":\"2019-03-19T20:53:39+00:00\",\"description\":\"After 26 years of workdays spent watching bacteria multiply, Richard Lenski has learned that evolution doesn\u2019t always occur in steps so slow and steady that change can\u2019t be observed.\",\"inLanguage\":\"en-US\",\"potentialAction\":[{\"@type\":\"ReadAction\",\"target\":[\"https:\/\/news.harvard.edu\/gazette\/story\/2014\/02\/evolution-in-real-time\/\"]}]},{\"@type\":\"ImageObject\",\"inLanguage\":\"en-US\",\"@id\":\"https:\/\/news.harvard.edu\/gazette\/story\/2014\/02\/evolution-in-real-time\/#primaryimage\",\"url\":\"https:\/\/news.harvard.edu\/wp-content\/uploads\/2014\/02\/021214_evolve_005-jpeg_605.jpg\",\"contentUrl\":\"https:\/\/news.harvard.edu\/wp-content\/uploads\/2014\/02\/021214_evolve_005-jpeg_605.jpg\",\"width\":605,\"height\":403},{\"@type\":\"WebSite\",\"@id\":\"https:\/\/news.harvard.edu\/gazette\/#website\",\"url\":\"https:\/\/news.harvard.edu\/gazette\/\",\"name\":\"Harvard Gazette\",\"description\":\"Official news from Harvard University covering innovation in teaching, learning, and research\",\"publisher\":{\"@id\":\"https:\/\/news.harvard.edu\/gazette\/#organization\"},\"potentialAction\":[{\"@type\":\"SearchAction\",\"target\":{\"@type\":\"EntryPoint\",\"urlTemplate\":\"https:\/\/news.harvard.edu\/gazette\/?s={search_term_string}\"},\"query-input\":{\"@type\":\"PropertyValueSpecification\",\"valueRequired\":true,\"valueName\":\"search_term_string\"}}],\"inLanguage\":\"en-US\"},{\"@type\":\"Organization\",\"@id\":\"https:\/\/news.harvard.edu\/gazette\/#organization\",\"name\":\"The Harvard Gazette\",\"url\":\"https:\/\/news.harvard.edu\/gazette\/\",\"logo\":{\"@type\":\"ImageObject\",\"inLanguage\":\"en-US\",\"@id\":\"https:\/\/news.harvard.edu\/gazette\/#\/schema\/logo\/image\/\",\"url\":\"https:\/\/news.harvard.edu\/wp-content\/uploads\/2023\/12\/Harvard_Gazette_logo.svg\",\"contentUrl\":\"https:\/\/news.harvard.edu\/wp-content\/uploads\/2023\/12\/Harvard_Gazette_logo.svg\",\"width\":164,\"height\":64,\"caption\":\"The Harvard Gazette\"},\"image\":{\"@id\":\"https:\/\/news.harvard.edu\/gazette\/#\/schema\/logo\/image\/\"}},{\"@type\":\"Person\",\"@id\":\"https:\/\/news.harvard.edu\/gazette\/#\/schema\/person\/78d028cf624923e92682268709ffbc4b\",\"name\":\"harvardgazette\"}]}<\/script>\n<!-- \/ Yoast SEO Premium plugin. -->","yoast_head_json":{"title":"Evolution in real time — Harvard Gazette","description":"After 26 years of workdays spent watching bacteria multiply, Richard Lenski has learned that evolution doesn\u2019t always occur in steps so slow and steady that change can\u2019t be observed.","robots":{"index":"index","follow":"follow","max-snippet":"max-snippet:-1","max-image-preview":"max-image-preview:large","max-video-preview":"max-video-preview:-1"},"canonical":"https:\/\/news.harvard.edu\/gazette\/story\/2014\/02\/evolution-in-real-time\/","og_locale":"en_US","og_type":"article","og_title":"Evolution in real time — Harvard Gazette","og_description":"After 26 years of workdays spent watching bacteria multiply, Richard Lenski has learned that evolution doesn\u2019t always occur in steps so slow and steady that change can\u2019t be observed.","og_url":"https:\/\/news.harvard.edu\/gazette\/story\/2014\/02\/evolution-in-real-time\/","og_site_name":"Harvard Gazette","article_published_time":"2014-02-13T20:13:26+00:00","article_modified_time":"2019-03-19T20:53:39+00:00","og_image":[{"width":605,"height":403,"url":"https:\/\/news.harvard.edu\/gazette\/wp-content\/uploads\/2014\/02\/021214_evolve_005-jpeg_605.jpg","type":"image\/jpeg"}],"author":"harvardgazette","twitter_card":"summary_large_image","schema":{"@context":"https:\/\/schema.org","@graph":[{"@type":"Article","@id":"https:\/\/news.harvard.edu\/gazette\/story\/2014\/02\/evolution-in-real-time\/#article","isPartOf":{"@id":"https:\/\/news.harvard.edu\/gazette\/story\/2014\/02\/evolution-in-real-time\/"},"author":{"name":"harvardgazette","@id":"https:\/\/news.harvard.edu\/gazette\/#\/schema\/person\/78d028cf624923e92682268709ffbc4b"},"headline":"Evolution in real time","datePublished":"2014-02-13T20:13:26+00:00","dateModified":"2019-03-19T20:53:39+00:00","mainEntityOfPage":{"@id":"https:\/\/news.harvard.edu\/gazette\/story\/2014\/02\/evolution-in-real-time\/"},"wordCount":985,"publisher":{"@id":"https:\/\/news.harvard.edu\/gazette\/#organization"},"image":{"@id":"https:\/\/news.harvard.edu\/gazette\/story\/2014\/02\/evolution-in-real-time\/#primaryimage"},"thumbnailUrl":"https:\/\/news.harvard.edu\/wp-content\/uploads\/2014\/02\/021214_evolve_005-jpeg_605.jpg","keywords":["Alvin Powell","Darwin","E. coli","Evolution","Harvard Museum of Natural History","Harvard Museums of Science & Culture","Jane Pickering","Jonathan Losos","Long-Term Experimental Evolution Project","Michigan State University","Mutation","natural selection","News Hub","Richard Lenski"],"articleSection":["Health"],"inLanguage":"en-US","copyrightYear":"2014","copyrightHolder":{"@id":"https:\/\/news.harvard.edu\/gazette\/#organization"}},{"@type":"WebPage","@id":"https:\/\/news.harvard.edu\/gazette\/story\/2014\/02\/evolution-in-real-time\/","url":"https:\/\/news.harvard.edu\/gazette\/story\/2014\/02\/evolution-in-real-time\/","name":"Evolution in real time — Harvard Gazette","isPartOf":{"@id":"https:\/\/news.harvard.edu\/gazette\/#website"},"primaryImageOfPage":{"@id":"https:\/\/news.harvard.edu\/gazette\/story\/2014\/02\/evolution-in-real-time\/#primaryimage"},"image":{"@id":"https:\/\/news.harvard.edu\/gazette\/story\/2014\/02\/evolution-in-real-time\/#primaryimage"},"thumbnailUrl":"https:\/\/news.harvard.edu\/wp-content\/uploads\/2014\/02\/021214_evolve_005-jpeg_605.jpg","datePublished":"2014-02-13T20:13:26+00:00","dateModified":"2019-03-19T20:53:39+00:00","description":"After 26 years of workdays spent watching bacteria multiply, Richard Lenski has learned that evolution doesn\u2019t always occur in steps so slow and steady that change can\u2019t be observed.","inLanguage":"en-US","potentialAction":[{"@type":"ReadAction","target":["https:\/\/news.harvard.edu\/gazette\/story\/2014\/02\/evolution-in-real-time\/"]}]},{"@type":"ImageObject","inLanguage":"en-US","@id":"https:\/\/news.harvard.edu\/gazette\/story\/2014\/02\/evolution-in-real-time\/#primaryimage","url":"https:\/\/news.harvard.edu\/wp-content\/uploads\/2014\/02\/021214_evolve_005-jpeg_605.jpg","contentUrl":"https:\/\/news.harvard.edu\/wp-content\/uploads\/2014\/02\/021214_evolve_005-jpeg_605.jpg","width":605,"height":403},{"@type":"WebSite","@id":"https:\/\/news.harvard.edu\/gazette\/#website","url":"https:\/\/news.harvard.edu\/gazette\/","name":"Harvard Gazette","description":"Official news from Harvard University covering innovation in teaching, learning, and research","publisher":{"@id":"https:\/\/news.harvard.edu\/gazette\/#organization"},"potentialAction":[{"@type":"SearchAction","target":{"@type":"EntryPoint","urlTemplate":"https:\/\/news.harvard.edu\/gazette\/?s={search_term_string}"},"query-input":{"@type":"PropertyValueSpecification","valueRequired":true,"valueName":"search_term_string"}}],"inLanguage":"en-US"},{"@type":"Organization","@id":"https:\/\/news.harvard.edu\/gazette\/#organization","name":"The Harvard Gazette","url":"https:\/\/news.harvard.edu\/gazette\/","logo":{"@type":"ImageObject","inLanguage":"en-US","@id":"https:\/\/news.harvard.edu\/gazette\/#\/schema\/logo\/image\/","url":"https:\/\/news.harvard.edu\/wp-content\/uploads\/2023\/12\/Harvard_Gazette_logo.svg","contentUrl":"https:\/\/news.harvard.edu\/wp-content\/uploads\/2023\/12\/Harvard_Gazette_logo.svg","width":164,"height":64,"caption":"The Harvard Gazette"},"image":{"@id":"https:\/\/news.harvard.edu\/gazette\/#\/schema\/logo\/image\/"}},{"@type":"Person","@id":"https:\/\/news.harvard.edu\/gazette\/#\/schema\/person\/78d028cf624923e92682268709ffbc4b","name":"harvardgazette"}]}},"parsely":{"version":"1.1.0","canonical_url":"https:\/\/news.harvard.edu\/gazette\/story\/2014\/02\/evolution-in-real-time\/","smart_links":{"inbound":0,"outbound":0},"traffic_boost_suggestions_count":0,"meta":{"@context":"https:\/\/schema.org","@type":"NewsArticle","headline":"Evolution in real time","url":"https:\/\/news.harvard.edu\/gazette\/story\/2014\/02\/evolution-in-real-time\/","mainEntityOfPage":{"@type":"WebPage","@id":"https:\/\/news.harvard.edu\/gazette\/story\/2014\/02\/evolution-in-real-time\/"},"thumbnailUrl":"https:\/\/news.harvard.edu\/wp-content\/uploads\/2014\/02\/021214_evolve_005-jpeg_605.jpg?w=150","image":{"@type":"ImageObject","url":"https:\/\/news.harvard.edu\/wp-content\/uploads\/2014\/02\/021214_evolve_005-jpeg_605.jpg"},"articleSection":"Health","author":[{"@type":"Person","name":"harvardgazette"}],"creator":["harvardgazette"],"publisher":{"@type":"Organization","name":"Harvard Gazette","logo":"https:\/\/news.harvard.edu\/gazette\/wp-content\/uploads\/2023\/12\/Harvard_Gazette_logo.svg"},"keywords":["alvin powell","darwin","e. coli","evolution","harvard museum of natural history","harvard museums of science & culture","jane pickering","jonathan losos","long-term experimental evolution project","michigan state university","mutation","natural selection","news hub","richard lenski"],"dateCreated":"2014-02-13T20:13:26Z","datePublished":"2014-02-13T20:13:26Z","dateModified":"2019-03-19T20:53:39Z"},"rendered":"<script type=\"application\/ld+json\" class=\"wp-parsely-metadata\">{\"@context\":\"https:\\\/\\\/schema.org\",\"@type\":\"NewsArticle\",\"headline\":\"Evolution in real time\",\"url\":\"https:\\\/\\\/news.harvard.edu\\\/gazette\\\/story\\\/2014\\\/02\\\/evolution-in-real-time\\\/\",\"mainEntityOfPage\":{\"@type\":\"WebPage\",\"@id\":\"https:\\\/\\\/news.harvard.edu\\\/gazette\\\/story\\\/2014\\\/02\\\/evolution-in-real-time\\\/\"},\"thumbnailUrl\":\"https:\\\/\\\/news.harvard.edu\\\/wp-content\\\/uploads\\\/2014\\\/02\\\/021214_evolve_005-jpeg_605.jpg?w=150\",\"image\":{\"@type\":\"ImageObject\",\"url\":\"https:\\\/\\\/news.harvard.edu\\\/wp-content\\\/uploads\\\/2014\\\/02\\\/021214_evolve_005-jpeg_605.jpg\"},\"articleSection\":\"Health\",\"author\":[{\"@type\":\"Person\",\"name\":\"harvardgazette\"}],\"creator\":[\"harvardgazette\"],\"publisher\":{\"@type\":\"Organization\",\"name\":\"Harvard Gazette\",\"logo\":\"https:\\\/\\\/news.harvard.edu\\\/gazette\\\/wp-content\\\/uploads\\\/2023\\\/12\\\/Harvard_Gazette_logo.svg\"},\"keywords\":[\"alvin powell\",\"darwin\",\"e. coli\",\"evolution\",\"harvard museum of natural history\",\"harvard museums of science & culture\",\"jane pickering\",\"jonathan losos\",\"long-term experimental evolution project\",\"michigan state university\",\"mutation\",\"natural selection\",\"news hub\",\"richard lenski\"],\"dateCreated\":\"2014-02-13T20:13:26Z\",\"datePublished\":\"2014-02-13T20:13:26Z\",\"dateModified\":\"2019-03-19T20:53:39Z\"}<\/script>","tracker_url":"https:\/\/cdn.parsely.com\/keys\/news.harvard.edu\/p.js"},"jetpack_featured_media_url":"https:\/\/news.harvard.edu\/wp-content\/uploads\/2014\/02\/021214_evolve_005-jpeg_605.jpg","has_blocks":true,"block_data":{"0":{"blockName":"harvard-gazette\/article-header","attrs":{"blockColorPalette":"","coloredHeading":"","creditText":"Photo by Melanie Rieders","displayDetails":"","displayTitle":"","categoryId":39644,"mediaAlt":"","mediaCaption":"Since 1988, Richard Lenski has watched E. coli bacteria multiply through 59,000 generations, a span that has allowed him to observe evolution in real time. He also found that one of the 12 bacterial lines he has maintained has developed into what he believes is a new species.","mediaId":152564,"mediaSize":"full","mediaType":"image","mediaUrl":"https:\/\/news.harvard.edu\/gazette\/wp-content\/uploads\/2014\/02\/021214_evolve_005-jpeg_605.jpg","poster":"","title":"Evolution in real time","subheading":"59,000 generations of bacteria, plus freezer, yield startling results","centeredImage":true,"className":"is-style-full-width-text-below","mediaHeight":403,"mediaWidth":605,"backgroundFixed":false,"backgroundTone":"light","coloredBackground":false,"displayOverlay":true,"fadeInText":false,"isAmbient":false,"mediaLength":"","mediaPosition":"","posterText":"","titleAbove":false,"useUncroppedImage":false,"lock":[],"metadata":[]},"innerBlocks":[],"innerHTML":"<figure class=\"wp-block-image\"><img alt=\"\" height=\"403\" loading=\"eager\" src=\"https:\/\/news.harvard.edu\/gazette\/wp-content\/uploads\/2014\/02\/021214_evolve_005-jpeg_605.jpg\" width=\"605\"\/><figcaption class=\"wp-element-caption\"><p class=\"wp-element-caption--caption\">Since 1988, Richard Lenski has watched E. coli bacteria multiply through 59,000 generations, a span that has allowed him to observe evolution in real time. He also found that one of the 12 bacterial lines he has maintained has developed into what he believes is a new species.<\/p><p class=\"wp-element-caption--credit\">Photo by Melanie Rieders<\/p><\/figcaption><\/figure>\n","innerContent":["<figure class=\"wp-block-image\"><img alt=\"\" height=\"403\" loading=\"eager\" src=\"https:\/\/news.harvard.edu\/gazette\/wp-content\/uploads\/2014\/02\/021214_evolve_005-jpeg_605.jpg\" width=\"605\"\/><figcaption class=\"wp-element-caption\"><p class=\"wp-element-caption--caption\">Since 1988, Richard Lenski has watched E. coli bacteria multiply through 59,000 generations, a span that has allowed him to observe evolution in real time. He also found that one of the 12 bacterial lines he has maintained has developed into what he believes is a new species.<\/p><p class=\"wp-element-caption--credit\">Photo by Melanie Rieders<\/p><\/figcaption><\/figure>\n"],"rendered":"<header\n\tclass=\"wp-block-harvard-gazette-article-header alignfull article-header is-style-full-width-text-below centered-image\"\n\tstyle=\" \"\n>\n\t<figure class=\"wp-block-image\"><img alt=\"\" height=\"403\" loading=\"eager\" src=\"https:\/\/news.harvard.edu\/gazette\/wp-content\/uploads\/2014\/02\/021214_evolve_005-jpeg_605.jpg\" width=\"605\"\/><figcaption class=\"wp-element-caption\"><p class=\"wp-element-caption--caption\">Since 1988, Richard Lenski has watched E. coli bacteria multiply through 59,000 generations, a span that has allowed him to observe evolution in real time. He also found that one of the 12 bacterial lines he has maintained has developed into what he believes is a new species.<\/p><p class=\"wp-element-caption--credit\">Photo by Melanie Rieders<\/p><\/figcaption><\/figure>\n\n\t<div class=\"article-header__content\">\n\t\t\t<a\n\t\t\tclass=\"article-header__category\"\n\t\t\thref=\"https:\/\/news.harvard.edu\/gazette\/section\/health\/\"\n\t\t>\n\t\t\tHealth\t\t<\/a>\n\t\t\n\t\t<h1 class=\"article-header__title wp-block-heading \">\n\t\tEvolution in real time\t<\/h1>\n\n\t\n\t\t\t<\/div>\n\t\t\n\t<div class=\"article-header__meta\">\n\t\t<div class=\"wp-block-post-author\">\n\t\t\t<address class=\"wp-block-post-author__content\">\n\t\t\t\t\t<p class=\"author wp-block-post-author__name\">\n\t\tAlvin Powell\t<\/p>\n\t\t\t<p class=\"wp-block-post-author__byline\">\n\t\t\tHarvard Staff Writer\t\t<\/p>\n\t\t\t\t\t<\/address>\n\t\t<\/div>\n\n\t\t<time class=\"article-header__date\" datetime=\"2014-02-13\">\n\t\t\tFebruary 13, 2014\t\t<\/time>\n\n\t\t<span class=\"article-header__reading-time\">\n\t\t\t5 min read\t\t<\/span>\n\t<\/div>\n\n\t\n\t\t\t<h2 class=\"article-header__subheading wp-block-heading\">\n\t\t\t59,000 generations of bacteria, plus freezer, yield startling results\t\t<\/h2>\n\t\t\n<\/header>\n"},"2":{"blockName":"core\/group","attrs":{"templateLock":false,"metadata":{"name":"Article content"},"align":"wide","layout":{"type":"constrained","justifyContent":"center"},"tagName":"div","lock":[],"className":"","style":[],"backgroundColor":"","textColor":"","gradient":"","fontSize":"","fontFamily":"","borderColor":"","ariaLabel":"","anchor":""},"innerBlocks":[{"blockName":"core\/freeform","attrs":{"content":"","lock":[],"metadata":[]},"innerBlocks":[],"innerHTML":"\n\t\t<p>After 26 years of workdays spent watching bacteria multiply, <a href=\"http:\/\/myxo.css.msu.edu\/\">Richard Lenski<\/a> has learned a thing or two.<\/p>\n<p>He\u2019s learned that naturalist Charles Darwin was wrong about some things. For one, evolution doesn\u2019t always occur in steps so slow and steady that changes can\u2019t be observed.<\/p>\n<p>Lenski also learned that a laboratory freezer can function as a time machine.<\/p>\n<p>A professor at <a href=\"http:\/\/www.msu.edu\/\">Michigan State University<\/a>, Lenski has watched <i>E. coli<\/i> bacteria multiply through 59,000 generations, a span that has allowed him to observe evolution in real time. Since his <a href=\"http:\/\/myxo.css.msu.edu\/ecoli\/index.html\">Long-Term Experimental Evolution Project<\/a> began in 1988, the bacteria have doubled in size, begun to mutate more quickly, and become more efficient at using the glucose in the solution where they\u2019re grown.<\/p>\n<p>More strikingly, however, he found that one of the 12 bacterial lines he has maintained has developed into what he believes is a new species, able to use a compound in the solution called citrate \u2014 a derivative of citric acid, like that found in some fruit \u2014 for food.<\/p>\n<p>Lenski described his groundbreaking work at Harvard\u2019s Mineralogical and Geological Museum on Wednesday during a talk sponsored by the <a href=\"http:\/\/www.hmnh.harvard.edu\">Harvard Museum of Natural History<\/a>, one of the <a href=\"http:\/\/www.hmsc.harvard.edu\">Harvard Museums of Science & Culture<\/a> (HMSC).<\/p>\n<p>His presentation, \u201cTime Travel in Experimental Evolution,\u201d was introduced by HMSC executive director <a href=\"http:\/\/hmsc.harvard.edu\/pages\/directors-welcome\">Jane Pickering<\/a> and by Jonathan Losos, the Monique and Philip Lehner Professor for the Study of Latin America and curator of herpetology in the <a href=\"http:\/\/www.mcz.harvard.edu\">Museum of Comparative Zoology<\/a>.<\/p>\n<p>Losos, who studies the behavior and evolution of Anolis lizards on Caribbean islands, called Lenski\u2019s long-running work \u201csimply extraordinary\u201d and said that his approach has been adopted by other researchers around the world.<\/p>\n<p>Losos said Lenski\u2019s talk was particularly appropriate because it occurred on the 205th anniversary of Darwin\u2019s birth. In the spirit of the ongoing Olympics, Losos said that if there were ever an all-star team of evolutionary biologists, Lenski would be its captain.<\/p>\n<p>While the ability to observe creatures with short reproductive times over thousands of generations has brought insights, Lenski said it was the use of the laboratory freezer that allowed the work to cross from observation into experimentation.<\/p>\n<p>Researchers periodically froze samples of <i>E. coli, <\/i>and because the frozen bacteria remained viable, scientists interested in particular evolutionary developments could directly compare modern populations against their ancestors. In addition, the development of cheap, accurate ways to analyze the genome has given researchers better analytical tools.<\/p>\n<p>One of the central questions Lenski has explored is the tension between evolution\u2019s opposing forces: the random mutations that initiate genetic change and the natural selection that shapes which mutations survive. Those forces, Lenski said, provide evolutionary pressure in different directions.<\/p>\n<p>Random genetic mutation pushes organisms to diversify, while natural selection is a homogenizing force, favoring characteristics that enhance survival under specific conditions.<\/p>\n<p>The experiment has run according to the same protocol since it began. <i>E. coli <\/i>bacteria are grown in the solution of glucose, a kind of sugar. The glucose is carefully measured so it eventually runs out and creates a period of scarcity and starvation before the bacteria are propagated the next day and transferred into a fresh solution. Every 75 days, roughly 500 generations, a portion of the cultures is frozen.<\/p>\n<p>Though the bacteria were originally genetically identical, they have evolved. Today\u2019s populations grow roughly 80 percent faster than the original lines, a development that Lenski called \u201ca beautiful example of adaptation by natural selection.\u201d<\/p>\n<p>An analysis of the 12 lines after 20,000 generations showed 45 mutations from the ancestral population among the bacteria\u2019s roughly 4,000 genes. Many of the same genes were mutated in all lines, but it was rarely exactly the same mutation within the genes, Lenski said. He equated the bacteria\u2019s evolutionary feats in the glucose-limited \u201cflask world\u201d with those of mountain climbers finding other routes to the peak.<\/p>\n<p>\u201cPopulations are climbing Mount Glucose in similar, though not identical, ways,\u201d Lenski said.<\/p>\n<p>After 30,000 generations, researchers noticed something strange. One population had evolved the ability to use a different carbon-based molecule in the solution, called citrate, as a power source.<\/p>\n<p>Researchers wondered whether it was the result of a rare, single mutation, or a more complex change involving a series of mutations over generations. To find out, one of Lenski\u2019s postdocs, Zachary Blount, took some of the frozen cells and grew them in a culture lacking glucose, with citrate as the only potential food source.<\/p>\n<p>After testing 10 trillion ancestral cells from early generations, he got no growth. But when he tested cells from the 20,000th generation on, he began to get results, eventually finding 19 mutants that could use citrate as a power source. The results showed that the citrate-eating mutation was most likely not the result of a single mutation, but one enabled by multiple changes over 20,000 generations.<\/p>\n<p>In further testing to determine if the new bacteria were different enough to qualify as a new species, Lenski\u2019s researchers found that beyond changes to the genes responsible for glucose and citrate consumption, other changes had occurred in the organism that had made it less fit to survive in a glucose-only environment,<\/p>\n<p>\u201cWe find they are getting less fit in the ancestral niche over time,\u201d Lenski said. \u201cI would argue that citrate users are \u2014 or are becoming \u2014 a new species.\u201d<\/p>\n<p>Lenski said he\u2019d like to see the experiment continue in the future, even after he has retired, because the bacteria continue to surprise.<\/p>\n<p>\u201cI call this the experiment that keeps on giving, because the bacteria continue to do interesting things,\u201d Lenski said. \u201cI\u2019d like this experiment to continue long after I\u2019m gone.\u201d<\/p>\n","innerContent":["\n\t\t<p>After 26 years of workdays spent watching bacteria multiply, <a href=\"http:\/\/myxo.css.msu.edu\/\">Richard Lenski<\/a> has learned a thing or two.<\/p>\n<p>He\u2019s learned that naturalist Charles Darwin was wrong about some things. For one, evolution doesn\u2019t always occur in steps so slow and steady that changes can\u2019t be observed.<\/p>\n<p>Lenski also learned that a laboratory freezer can function as a time machine.<\/p>\n<p>A professor at <a href=\"http:\/\/www.msu.edu\/\">Michigan State University<\/a>, Lenski has watched <i>E. coli<\/i> bacteria multiply through 59,000 generations, a span that has allowed him to observe evolution in real time. Since his <a href=\"http:\/\/myxo.css.msu.edu\/ecoli\/index.html\">Long-Term Experimental Evolution Project<\/a> began in 1988, the bacteria have doubled in size, begun to mutate more quickly, and become more efficient at using the glucose in the solution where they\u2019re grown.<\/p>\n<p>More strikingly, however, he found that one of the 12 bacterial lines he has maintained has developed into what he believes is a new species, able to use a compound in the solution called citrate \u2014 a derivative of citric acid, like that found in some fruit \u2014 for food.<\/p>\n<p>Lenski described his groundbreaking work at Harvard\u2019s Mineralogical and Geological Museum on Wednesday during a talk sponsored by the <a href=\"http:\/\/www.hmnh.harvard.edu\">Harvard Museum of Natural History<\/a>, one of the <a href=\"http:\/\/www.hmsc.harvard.edu\">Harvard Museums of Science & Culture<\/a> (HMSC).<\/p>\n<p>His presentation, \u201cTime Travel in Experimental Evolution,\u201d was introduced by HMSC executive director <a href=\"http:\/\/hmsc.harvard.edu\/pages\/directors-welcome\">Jane Pickering<\/a> and by Jonathan Losos, the Monique and Philip Lehner Professor for the Study of Latin America and curator of herpetology in the <a href=\"http:\/\/www.mcz.harvard.edu\">Museum of Comparative Zoology<\/a>.<\/p>\n<p>Losos, who studies the behavior and evolution of Anolis lizards on Caribbean islands, called Lenski\u2019s long-running work \u201csimply extraordinary\u201d and said that his approach has been adopted by other researchers around the world.<\/p>\n<p>Losos said Lenski\u2019s talk was particularly appropriate because it occurred on the 205th anniversary of Darwin\u2019s birth. In the spirit of the ongoing Olympics, Losos said that if there were ever an all-star team of evolutionary biologists, Lenski would be its captain.<\/p>\n<p>While the ability to observe creatures with short reproductive times over thousands of generations has brought insights, Lenski said it was the use of the laboratory freezer that allowed the work to cross from observation into experimentation.<\/p>\n<p>Researchers periodically froze samples of <i>E. coli, <\/i>and because the frozen bacteria remained viable, scientists interested in particular evolutionary developments could directly compare modern populations against their ancestors. In addition, the development of cheap, accurate ways to analyze the genome has given researchers better analytical tools.<\/p>\n<p>One of the central questions Lenski has explored is the tension between evolution\u2019s opposing forces: the random mutations that initiate genetic change and the natural selection that shapes which mutations survive. Those forces, Lenski said, provide evolutionary pressure in different directions.<\/p>\n<p>Random genetic mutation pushes organisms to diversify, while natural selection is a homogenizing force, favoring characteristics that enhance survival under specific conditions.<\/p>\n<p>The experiment has run according to the same protocol since it began. <i>E. coli <\/i>bacteria are grown in the solution of glucose, a kind of sugar. The glucose is carefully measured so it eventually runs out and creates a period of scarcity and starvation before the bacteria are propagated the next day and transferred into a fresh solution. Every 75 days, roughly 500 generations, a portion of the cultures is frozen.<\/p>\n<p>Though the bacteria were originally genetically identical, they have evolved. Today\u2019s populations grow roughly 80 percent faster than the original lines, a development that Lenski called \u201ca beautiful example of adaptation by natural selection.\u201d<\/p>\n<p>An analysis of the 12 lines after 20,000 generations showed 45 mutations from the ancestral population among the bacteria\u2019s roughly 4,000 genes. Many of the same genes were mutated in all lines, but it was rarely exactly the same mutation within the genes, Lenski said. He equated the bacteria\u2019s evolutionary feats in the glucose-limited \u201cflask world\u201d with those of mountain climbers finding other routes to the peak.<\/p>\n<p>\u201cPopulations are climbing Mount Glucose in similar, though not identical, ways,\u201d Lenski said.<\/p>\n<p>After 30,000 generations, researchers noticed something strange. One population had evolved the ability to use a different carbon-based molecule in the solution, called citrate, as a power source.<\/p>\n<p>Researchers wondered whether it was the result of a rare, single mutation, or a more complex change involving a series of mutations over generations. To find out, one of Lenski\u2019s postdocs, Zachary Blount, took some of the frozen cells and grew them in a culture lacking glucose, with citrate as the only potential food source.<\/p>\n<p>After testing 10 trillion ancestral cells from early generations, he got no growth. But when he tested cells from the 20,000th generation on, he began to get results, eventually finding 19 mutants that could use citrate as a power source. The results showed that the citrate-eating mutation was most likely not the result of a single mutation, but one enabled by multiple changes over 20,000 generations.<\/p>\n<p>In further testing to determine if the new bacteria were different enough to qualify as a new species, Lenski\u2019s researchers found that beyond changes to the genes responsible for glucose and citrate consumption, other changes had occurred in the organism that had made it less fit to survive in a glucose-only environment,<\/p>\n<p>\u201cWe find they are getting less fit in the ancestral niche over time,\u201d Lenski said. \u201cI would argue that citrate users are \u2014 or are becoming \u2014 a new species.\u201d<\/p>\n<p>Lenski said he\u2019d like to see the experiment continue in the future, even after he has retired, because the bacteria continue to surprise.<\/p>\n<p>\u201cI call this the experiment that keeps on giving, because the bacteria continue to do interesting things,\u201d Lenski said. \u201cI\u2019d like this experiment to continue long after I\u2019m gone.\u201d<\/p>\n"],"rendered":"\n\t\t<p>After 26 years of workdays spent watching bacteria multiply, <a href=\"http:\/\/myxo.css.msu.edu\/\">Richard Lenski<\/a> has learned a thing or two.<\/p>\n<p>He\u2019s learned that naturalist Charles Darwin was wrong about some things. For one, evolution doesn\u2019t always occur in steps so slow and steady that changes can\u2019t be observed.<\/p>\n<p>Lenski also learned that a laboratory freezer can function as a time machine.<\/p>\n<p>A professor at <a href=\"http:\/\/www.msu.edu\/\">Michigan State University<\/a>, Lenski has watched <i>E. coli<\/i> bacteria multiply through 59,000 generations, a span that has allowed him to observe evolution in real time. Since his <a href=\"http:\/\/myxo.css.msu.edu\/ecoli\/index.html\">Long-Term Experimental Evolution Project<\/a> began in 1988, the bacteria have doubled in size, begun to mutate more quickly, and become more efficient at using the glucose in the solution where they\u2019re grown.<\/p>\n<p>More strikingly, however, he found that one of the 12 bacterial lines he has maintained has developed into what he believes is a new species, able to use a compound in the solution called citrate \u2014 a derivative of citric acid, like that found in some fruit \u2014 for food.<\/p>\n<p>Lenski described his groundbreaking work at Harvard\u2019s Mineralogical and Geological Museum on Wednesday during a talk sponsored by the <a href=\"http:\/\/www.hmnh.harvard.edu\">Harvard Museum of Natural History<\/a>, one of the <a href=\"http:\/\/www.hmsc.harvard.edu\">Harvard Museums of Science & Culture<\/a> (HMSC).<\/p>\n<p>His presentation, \u201cTime Travel in Experimental Evolution,\u201d was introduced by HMSC executive director <a href=\"http:\/\/hmsc.harvard.edu\/pages\/directors-welcome\">Jane Pickering<\/a> and by Jonathan Losos, the Monique and Philip Lehner Professor for the Study of Latin America and curator of herpetology in the <a href=\"http:\/\/www.mcz.harvard.edu\">Museum of Comparative Zoology<\/a>.<\/p>\n<p>Losos, who studies the behavior and evolution of Anolis lizards on Caribbean islands, called Lenski\u2019s long-running work \u201csimply extraordinary\u201d and said that his approach has been adopted by other researchers around the world.<\/p>\n<p>Losos said Lenski\u2019s talk was particularly appropriate because it occurred on the 205th anniversary of Darwin\u2019s birth. In the spirit of the ongoing Olympics, Losos said that if there were ever an all-star team of evolutionary biologists, Lenski would be its captain.<\/p>\n<p>While the ability to observe creatures with short reproductive times over thousands of generations has brought insights, Lenski said it was the use of the laboratory freezer that allowed the work to cross from observation into experimentation.<\/p>\n<p>Researchers periodically froze samples of <i>E. coli, <\/i>and because the frozen bacteria remained viable, scientists interested in particular evolutionary developments could directly compare modern populations against their ancestors. In addition, the development of cheap, accurate ways to analyze the genome has given researchers better analytical tools.<\/p>\n<p>One of the central questions Lenski has explored is the tension between evolution\u2019s opposing forces: the random mutations that initiate genetic change and the natural selection that shapes which mutations survive. Those forces, Lenski said, provide evolutionary pressure in different directions.<\/p>\n<p>Random genetic mutation pushes organisms to diversify, while natural selection is a homogenizing force, favoring characteristics that enhance survival under specific conditions.<\/p>\n<p>The experiment has run according to the same protocol since it began. <i>E. coli <\/i>bacteria are grown in the solution of glucose, a kind of sugar. The glucose is carefully measured so it eventually runs out and creates a period of scarcity and starvation before the bacteria are propagated the next day and transferred into a fresh solution. Every 75 days, roughly 500 generations, a portion of the cultures is frozen.<\/p>\n<p>Though the bacteria were originally genetically identical, they have evolved. Today\u2019s populations grow roughly 80 percent faster than the original lines, a development that Lenski called \u201ca beautiful example of adaptation by natural selection.\u201d<\/p>\n<p>An analysis of the 12 lines after 20,000 generations showed 45 mutations from the ancestral population among the bacteria\u2019s roughly 4,000 genes. Many of the same genes were mutated in all lines, but it was rarely exactly the same mutation within the genes, Lenski said. He equated the bacteria\u2019s evolutionary feats in the glucose-limited \u201cflask world\u201d with those of mountain climbers finding other routes to the peak.<\/p>\n<p>\u201cPopulations are climbing Mount Glucose in similar, though not identical, ways,\u201d Lenski said.<\/p>\n<p>After 30,000 generations, researchers noticed something strange. One population had evolved the ability to use a different carbon-based molecule in the solution, called citrate, as a power source.<\/p>\n<p>Researchers wondered whether it was the result of a rare, single mutation, or a more complex change involving a series of mutations over generations. To find out, one of Lenski\u2019s postdocs, Zachary Blount, took some of the frozen cells and grew them in a culture lacking glucose, with citrate as the only potential food source.<\/p>\n<p>After testing 10 trillion ancestral cells from early generations, he got no growth. But when he tested cells from the 20,000th generation on, he began to get results, eventually finding 19 mutants that could use citrate as a power source. The results showed that the citrate-eating mutation was most likely not the result of a single mutation, but one enabled by multiple changes over 20,000 generations.<\/p>\n<p>In further testing to determine if the new bacteria were different enough to qualify as a new species, Lenski\u2019s researchers found that beyond changes to the genes responsible for glucose and citrate consumption, other changes had occurred in the organism that had made it less fit to survive in a glucose-only environment,<\/p>\n<p>\u201cWe find they are getting less fit in the ancestral niche over time,\u201d Lenski said. \u201cI would argue that citrate users are \u2014 or are becoming \u2014 a new species.\u201d<\/p>\n<p>Lenski said he\u2019d like to see the experiment continue in the future, even after he has retired, because the bacteria continue to surprise.<\/p>\n<p>\u201cI call this the experiment that keeps on giving, because the bacteria continue to do interesting things,\u201d Lenski said. \u201cI\u2019d like this experiment to continue long after I\u2019m gone.\u201d<\/p>\n"}],"innerHTML":"\n<div class=\"wp-block-group alignwide\">\n\n\n\n<\/div>\n","innerContent":["\n<div class=\"wp-block-group alignwide\">\n\n","\n\n<\/div>\n"],"rendered":"\n<div class=\"wp-block-group alignwide has-global-padding is-content-justification-center is-layout-constrained wp-block-group-is-layout-constrained\">\n\n\n\t\t<p>After 26 years of workdays spent watching bacteria multiply, <a href=\"http:\/\/myxo.css.msu.edu\/\">Richard Lenski<\/a> has learned a thing or two.<\/p>\n<p>He\u2019s learned that naturalist Charles Darwin was wrong about some things. For one, evolution doesn\u2019t always occur in steps so slow and steady that changes can\u2019t be observed.<\/p>\n<p>Lenski also learned that a laboratory freezer can function as a time machine.<\/p>\n<p>A professor at <a href=\"http:\/\/www.msu.edu\/\">Michigan State University<\/a>, Lenski has watched <i>E. coli<\/i> bacteria multiply through 59,000 generations, a span that has allowed him to observe evolution in real time. Since his <a href=\"http:\/\/myxo.css.msu.edu\/ecoli\/index.html\">Long-Term Experimental Evolution Project<\/a> began in 1988, the bacteria have doubled in size, begun to mutate more quickly, and become more efficient at using the glucose in the solution where they\u2019re grown.<\/p>\n<p>More strikingly, however, he found that one of the 12 bacterial lines he has maintained has developed into what he believes is a new species, able to use a compound in the solution called citrate \u2014 a derivative of citric acid, like that found in some fruit \u2014 for food.<\/p>\n<p>Lenski described his groundbreaking work at Harvard\u2019s Mineralogical and Geological Museum on Wednesday during a talk sponsored by the <a href=\"http:\/\/www.hmnh.harvard.edu\">Harvard Museum of Natural History<\/a>, one of the <a href=\"http:\/\/www.hmsc.harvard.edu\">Harvard Museums of Science & Culture<\/a> (HMSC).<\/p>\n<p>His presentation, \u201cTime Travel in Experimental Evolution,\u201d was introduced by HMSC executive director <a href=\"http:\/\/hmsc.harvard.edu\/pages\/directors-welcome\">Jane Pickering<\/a> and by Jonathan Losos, the Monique and Philip Lehner Professor for the Study of Latin America and curator of herpetology in the <a href=\"http:\/\/www.mcz.harvard.edu\">Museum of Comparative Zoology<\/a>.<\/p>\n<p>Losos, who studies the behavior and evolution of Anolis lizards on Caribbean islands, called Lenski\u2019s long-running work \u201csimply extraordinary\u201d and said that his approach has been adopted by other researchers around the world.<\/p>\n<p>Losos said Lenski\u2019s talk was particularly appropriate because it occurred on the 205th anniversary of Darwin\u2019s birth. In the spirit of the ongoing Olympics, Losos said that if there were ever an all-star team of evolutionary biologists, Lenski would be its captain.<\/p>\n<p>While the ability to observe creatures with short reproductive times over thousands of generations has brought insights, Lenski said it was the use of the laboratory freezer that allowed the work to cross from observation into experimentation.<\/p>\n<p>Researchers periodically froze samples of <i>E. coli, <\/i>and because the frozen bacteria remained viable, scientists interested in particular evolutionary developments could directly compare modern populations against their ancestors. In addition, the development of cheap, accurate ways to analyze the genome has given researchers better analytical tools.<\/p>\n<p>One of the central questions Lenski has explored is the tension between evolution\u2019s opposing forces: the random mutations that initiate genetic change and the natural selection that shapes which mutations survive. Those forces, Lenski said, provide evolutionary pressure in different directions.<\/p>\n<p>Random genetic mutation pushes organisms to diversify, while natural selection is a homogenizing force, favoring characteristics that enhance survival under specific conditions.<\/p>\n<p>The experiment has run according to the same protocol since it began. <i>E. coli <\/i>bacteria are grown in the solution of glucose, a kind of sugar. The glucose is carefully measured so it eventually runs out and creates a period of scarcity and starvation before the bacteria are propagated the next day and transferred into a fresh solution. Every 75 days, roughly 500 generations, a portion of the cultures is frozen.<\/p>\n<p>Though the bacteria were originally genetically identical, they have evolved. Today\u2019s populations grow roughly 80 percent faster than the original lines, a development that Lenski called \u201ca beautiful example of adaptation by natural selection.\u201d<\/p>\n<p>An analysis of the 12 lines after 20,000 generations showed 45 mutations from the ancestral population among the bacteria\u2019s roughly 4,000 genes. Many of the same genes were mutated in all lines, but it was rarely exactly the same mutation within the genes, Lenski said. He equated the bacteria\u2019s evolutionary feats in the glucose-limited \u201cflask world\u201d with those of mountain climbers finding other routes to the peak.<\/p>\n<p>\u201cPopulations are climbing Mount Glucose in similar, though not identical, ways,\u201d Lenski said.<\/p>\n<p>After 30,000 generations, researchers noticed something strange. One population had evolved the ability to use a different carbon-based molecule in the solution, called citrate, as a power source.<\/p>\n<p>Researchers wondered whether it was the result of a rare, single mutation, or a more complex change involving a series of mutations over generations. To find out, one of Lenski\u2019s postdocs, Zachary Blount, took some of the frozen cells and grew them in a culture lacking glucose, with citrate as the only potential food source.<\/p>\n<p>After testing 10 trillion ancestral cells from early generations, he got no growth. But when he tested cells from the 20,000th generation on, he began to get results, eventually finding 19 mutants that could use citrate as a power source. The results showed that the citrate-eating mutation was most likely not the result of a single mutation, but one enabled by multiple changes over 20,000 generations.<\/p>\n<p>In further testing to determine if the new bacteria were different enough to qualify as a new species, Lenski\u2019s researchers found that beyond changes to the genes responsible for glucose and citrate consumption, other changes had occurred in the organism that had made it less fit to survive in a glucose-only environment,<\/p>\n<p>\u201cWe find they are getting less fit in the ancestral niche over time,\u201d Lenski said. \u201cI would argue that citrate users are \u2014 or are becoming \u2014 a new species.\u201d<\/p>\n<p>Lenski said he\u2019d like to see the experiment continue in the future, even after he has retired, because the bacteria continue to surprise.<\/p>\n<p>\u201cI call this the experiment that keeps on giving, because the bacteria continue to do interesting things,\u201d Lenski said. \u201cI\u2019d like this experiment to continue long after I\u2019m gone.\u201d<\/p>\n\n\n<\/div>\n"}},"jetpack-related-posts":[{"id":230613,"url":"https:\/\/news.harvard.edu\/gazette\/story\/2017\/10\/evolution-book\/","url_meta":{"origin":152562,"position":0},"title":"A new era in the study of evolution","author":"gazettejohnbaglione","date":"October 2, 2017","format":false,"excerpt":"Harvard biologist Jonathan Losos talks about his new book, \u201cImprobable Destinies: Fate, Chance, and the Future of Evolution.\u201d","rel":"","context":"In "Health"","block_context":{"text":"Health","link":"https:\/\/news.harvard.edu\/gazette\/section\/health\/"},"img":{"alt_text":"","src":"https:\/\/news.harvard.edu\/wp-content\/uploads\/2017\/09\/092017_losos_024_605.jpg?resize=350%2C200","width":350,"height":200,"srcset":"https:\/\/news.harvard.edu\/wp-content\/uploads\/2017\/09\/092017_losos_024_605.jpg?resize=350%2C200 1x, https:\/\/news.harvard.edu\/wp-content\/uploads\/2017\/09\/092017_losos_024_605.jpg?resize=525%2C300 1.5x"},"classes":[]},{"id":171780,"url":"https:\/\/news.harvard.edu\/gazette\/story\/2015\/06\/alone-with-evolution\/","url_meta":{"origin":152562,"position":1},"title":"Alone with evolution","author":"harvardgazette","date":"June 23, 2015","format":false,"excerpt":"Efforts by Harvard faculty to understand island evolution form the centerpiece of a new exhibition at the Harvard Museum of Natural History.","rel":"","context":"In "Health"","block_context":{"text":"Health","link":"https:\/\/news.harvard.edu\/gazette\/section\/health\/"},"img":{"alt_text":"","src":"https:\/\/news.harvard.edu\/wp-content\/uploads\/2015\/06\/060115_islands_091_605_1.jpg?resize=350%2C200","width":350,"height":200,"srcset":"https:\/\/news.harvard.edu\/wp-content\/uploads\/2015\/06\/060115_islands_091_605_1.jpg?resize=350%2C200 1x, https:\/\/news.harvard.edu\/wp-content\/uploads\/2015\/06\/060115_islands_091_605_1.jpg?resize=525%2C300 1.5x"},"classes":[]},{"id":60066,"url":"https:\/\/news.harvard.edu\/gazette\/story\/2006\/03\/evolving-ideas\/","url_meta":{"origin":152562,"position":2},"title":"Evolving ideas","author":"harvardgazette","date":"March 2, 2006","format":false,"excerpt":"Is the problem with evolution A) people don't believe in it; B) people believe in it but don't understand it; or C) evolution comes packaged with troubling implications that we don't want to accept? According to speakers at a spirited Askwith Education Forum - \"How Do We Teach Evolution\" -\u2026","rel":"","context":"In "Campus & Community"","block_context":{"text":"Campus & Community","link":"https:\/\/news.harvard.edu\/gazette\/section\/campus-community\/"},"img":{"alt_text":"","src":"","width":0,"height":0},"classes":[]},{"id":301935,"url":"https:\/\/news.harvard.edu\/gazette\/story\/2020\/04\/human-knee-evolved-in-lockstep-with-osteoarthritis-harvard-study-says\/","url_meta":{"origin":152562,"position":3},"title":"A flawed masterpiece","author":"harvardgazette","date":"April 7, 2020","format":false,"excerpt":"In a new paper published in Cell, Harvard researchers exploring the genetic features that help make the knee possible found that the regulatory switches involved in its development also play a role in a partially heritable disease.","rel":"","context":"In "Health"","block_context":{"text":"Health","link":"https:\/\/news.harvard.edu\/gazette\/section\/health\/"},"img":{"alt_text":"Evolution of the knee.","src":"https:\/\/news.harvard.edu\/wp-content\/uploads\/2020\/04\/newCAPELLINI_knee_osteoarthritis_Cell_2020.jpg?resize=350%2C200","width":350,"height":200,"srcset":"https:\/\/news.harvard.edu\/wp-content\/uploads\/2020\/04\/newCAPELLINI_knee_osteoarthritis_Cell_2020.jpg?resize=350%2C200 1x, https:\/\/news.harvard.edu\/wp-content\/uploads\/2020\/04\/newCAPELLINI_knee_osteoarthritis_Cell_2020.jpg?resize=525%2C300 1.5x, https:\/\/news.harvard.edu\/wp-content\/uploads\/2020\/04\/newCAPELLINI_knee_osteoarthritis_Cell_2020.jpg?resize=700%2C400 2x"},"classes":[]},{"id":164700,"url":"https:\/\/news.harvard.edu\/gazette\/story\/2014\/12\/reader-favorites-for-2014\/","url_meta":{"origin":152562,"position":4},"title":"Reader favorites for 2014","author":"harvardgazette","date":"December 23, 2014","format":false,"excerpt":"In 2014, the Harvard Gazette featured major news from the University. From treatments for diabetes and depression to snapshots of Commencement, the Gazette captured the essence of the Harvard community.","rel":"","context":"In "Campus & Community"","block_context":{"text":"Campus & Community","link":"https:\/\/news.harvard.edu\/gazette\/section\/campus-community\/"},"img":{"alt_text":"","src":"https:\/\/news.harvard.edu\/wp-content\/uploads\/2014\/12\/122314_2014review_6052-b.jpg?resize=350%2C200","width":350,"height":200,"srcset":"https:\/\/news.harvard.edu\/wp-content\/uploads\/2014\/12\/122314_2014review_6052-b.jpg?resize=350%2C200 1x, https:\/\/news.harvard.edu\/wp-content\/uploads\/2014\/12\/122314_2014review_6052-b.jpg?resize=525%2C300 1.5x"},"classes":[]},{"id":109621,"url":"https:\/\/news.harvard.edu\/gazette\/story\/2012\/05\/the-whys-of-religion-vs-evolution\/","url_meta":{"origin":152562,"position":5},"title":"The whys of religion vs. evolution","author":"harvardgazette","date":"May 8, 2012","format":false,"excerpt":"University of Chicago evolutionary biologist Jerry Coyne says that dysfunction within American society promotes high levels of religious belief that in turn blocks general acceptance of evolutionary theories.","rel":"","context":"In "Science & Tech"","block_context":{"text":"Science & Tech","link":"https:\/\/news.harvard.edu\/gazette\/section\/science-technology\/"},"img":{"alt_text":"","src":"https:\/\/news.harvard.edu\/wp-content\/uploads\/2012\/05\/050212_coyne_170_605.jpg?resize=350%2C200","width":350,"height":200,"srcset":"https:\/\/news.harvard.edu\/wp-content\/uploads\/2012\/05\/050212_coyne_170_605.jpg?resize=350%2C200 1x, https:\/\/news.harvard.edu\/wp-content\/uploads\/2012\/05\/050212_coyne_170_605.jpg?resize=525%2C300 1.5x"},"classes":[]}],"jetpack_sharing_enabled":true,"_links":{"self":[{"href":"https:\/\/news.harvard.edu\/gazette\/wp-json\/wp\/v2\/posts\/152562","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/news.harvard.edu\/gazette\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/news.harvard.edu\/gazette\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/news.harvard.edu\/gazette\/wp-json\/wp\/v2\/users\/105622744"}],"replies":[{"embeddable":true,"href":"https:\/\/news.harvard.edu\/gazette\/wp-json\/wp\/v2\/comments?post=152562"}],"version-history":[{"count":1,"href":"https:\/\/news.harvard.edu\/gazette\/wp-json\/wp\/v2\/posts\/152562\/revisions"}],"predecessor-version":[{"id":268769,"href":"https:\/\/news.harvard.edu\/gazette\/wp-json\/wp\/v2\/posts\/152562\/revisions\/268769"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/news.harvard.edu\/gazette\/wp-json\/wp\/v2\/media\/152564"}],"wp:attachment":[{"href":"https:\/\/news.harvard.edu\/gazette\/wp-json\/wp\/v2\/media?parent=152562"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/news.harvard.edu\/gazette\/wp-json\/wp\/v2\/categories?post=152562"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/news.harvard.edu\/gazette\/wp-json\/wp\/v2\/tags?post=152562"},{"taxonomy":"format","embeddable":true,"href":"https:\/\/news.harvard.edu\/gazette\/wp-json\/wp\/v2\/gazette-formats?post=152562"},{"taxonomy":"series","embeddable":true,"href":"https:\/\/news.harvard.edu\/gazette\/wp-json\/wp\/v2\/series?post=152562"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}