{"681378":{"#nid":"681378","#data":{"type":"news","title":"Scientists uncover key mechanism in evolution: Whole-genome duplication drives long-term adaptation","body":[{"value":"\u003Cp\u003ESometimes, the most significant scientific discoveries happen by accident.\u0026nbsp;\u003C\/p\u003E\u003Cp\u003EScientists have long known that whole-genome duplication (WGD) \u2014 the process by which organisms copy all their genetic material \u2014 plays an important role in evolution. But understanding just how WGD arises, persists, and drives adaptation has remained poorly understood.\u003C\/p\u003E\u003Cp\u003EIn an unexpected turn, scientists at Georgia Tech not only uncovered how WGD occurs, but also how it stays stable over thousands of generations of evolution in the lab. \u0026nbsp;\u003C\/p\u003E\u003Cp\u003EThe new study was led by \u003Ca href=\u0022https:\/\/biosciences.gatech.edu\/people\/will-ratcliff\u0022\u003EWilliam Ratcliff\u003C\/a\u003E, professor in the \u003Ca href=\u0022https:\/\/biosciences.gatech.edu\/\u0022\u003ESchool of Biological Sciences,\u003C\/a\u003E and Kai Tong, a former Ph.D. student in Ratcliff\u0027s lab who is now a postdoctoral fellow at Boston University.\u003C\/p\u003E\u003Cp\u003ETheir paper, \u201c\u003Ca href=\u0022https:\/\/www.nature.com\/articles\/s41586-025-08689-6\u0022\u003EGenome duplication in a long-term multicellularity evolution experiment\u003C\/a\u003E,\u201d\u003Cstrong\u003E\u0026nbsp;\u003C\/strong\u003Ewas published in \u003Cem\u003ENature\u003C\/em\u003E as \u003Ca href=\u0022https:\/\/www.nature.com\/nature\/volumes\/639\/issues\/8055\u0022\u003Ethe journal\u2019s cover story\u003C\/a\u003E in March.\u0026nbsp;\u003C\/p\u003E\u003Cp\u003E\u0022We set out to explore how organisms make the transition to multicellularity, but discovering the role of WGD in this process was completely serendipitous,\u0022 said Ratcliff. \u0022This research provides new insights into how WGD can emerge, persist over long periods, and fuel evolutionary innovation. That\u2019s truly exciting.\u0022\u003C\/p\u003E\u003Cp\u003E\u003Cstrong\u003EA secret hidden in the data\u003C\/strong\u003E\u003C\/p\u003E\u003Cp\u003EIn 2018, Ratcliff\u2019s lab launched an experiment to explore open-ended multicellular evolution. The \u003Ca href=\u0022https:\/\/research.gatech.edu\/journey-origins-multicellular-life-long-term-experimental-evolution-lab\u0022\u003EMulticellular Long-Term Evolution Experiment\u003C\/a\u003E (MuLTEE) uses \u201csnowflake\u201d yeast (\u003Cem\u003ESaccharomyces cerevisiae\u003C\/em\u003E) as a medium, evolving it from a single cell to increasingly complex multicellular organisms. The researchers do this by selecting yeast cells for larger size on a daily basis.\u0026nbsp;\u003C\/p\u003E\u003Cp\u003E\u0022These long-term evolution studies help us answer big questions about how organisms adapt and evolve,\u201d said Tong. \u201cThey often reveal the unexpected and expand our understanding of evolutionary processes.\u0022\u0026nbsp;\u003C\/p\u003E\u003Cp\u003EThat\u2019s exactly what happened when Ozan Bozdag, a research faculty member in Ratcliff\u2019s lab, noticed something unusual in the snowflake yeast. Bozdag observed the yeast when it was 1,000 days old and saw characteristics suggesting it might have gone from diploidy (having two sets of chromosomes) to tetraploidy (having four).\u003C\/p\u003E\u003Cp\u003EDecades of lab experiments show that tetraploidy is characteristically unstable, reverting back to diploidy within a few hundred generations. For this reason, Tong was skeptical that WGD had occurred and persisted for thousands of generations in the MuLTEE. If true, it would be the first time a WGD arose spontaneously and persisted in the lab.\u003C\/p\u003E\u003Cp\u003EAfter taking measurements of the evolved yeast, Tong found that they had duplicated their genomes very early \u2014 within the first 50 days of the MuLTEE. Strikingly, these tetraploid genomes persisted for more than 1,000 days, continuing to thrive despite the usual instability of WGD in laboratory conditions.\u0026nbsp;\u003C\/p\u003E\u003Cp\u003EThe team discovered that WGD arose and stuck around because it gave the yeast an immediate advantage in growing larger, longer cells and forming bigger multicellular clusters, which are favored under the size selection in the MuLTEE.\u0026nbsp;\u003C\/p\u003E\u003Cp\u003EFurther experiments showed that while WGD in snowflake yeast is normally unstable, it persisted in the MuLTEE because the larger, multicellular clusters had a survival advantage. This stability allowed the yeast to undergo genetic changes, with aneuploidy (the condition of having an abnormal number of chromosomes) playing a key role in the development of multicellularity. As a result, MuLTEE became the longest-running polyploidy evolution experiment, offering new insights into how genome duplication contributes to biological complexity.\u003C\/p\u003E\u003Cp\u003E\u003Cstrong\u003EA MuLTEE-talented team\u003C\/strong\u003E\u003C\/p\u003E\u003Cp\u003ERatcliff emphasized that rigorous undergraduate research played a critical role in their unexpected breakthrough. Four undergraduate students were integral to the success of the experiment, joining the research early in their education at Georgia Tech.\u0026nbsp;\u003C\/p\u003E\u003Cp\u003E\u0022This kind of authentic research experience is life-changing and career-altering for our students,\u201d Ratcliff said. \u201cYou can\u2019t get this level of learning in a classroom.\u0022\u0026nbsp;\u003C\/p\u003E\u003Cp\u003EVivian Cheng, who joined Ratcliff\u2019s lab as a first-year and graduated in 2022, took on the challenge of genetically engineering diploid and tetraploid yeast strains along with another student. Ratcliff and Tong ended up using these same strains as a major part of their analysis.\u0026nbsp;\u003C\/p\u003E\u003Cp\u003E\u201cThis work is another step toward understanding the various factors that contribute to the evolution of multicellularity,\u201d said Cheng, now a Ph.D. candidate at the University of Illinois Urbana-Champaign. \u201cIt\u0027s super cool to see how this single factor of ploidy level affects selection in these yeast cells.\u201d\u003C\/p\u003E\u003Cp\u003ERatcliff notes that some of his team\u2019s most significant findings could never have been anticipated when they started MuLTEE. But that\u2019s the whole point, he says.\u0026nbsp;\u003C\/p\u003E\u003Cp\u003E\u201cThe most far-reaching results from these experiments are often the ones we weren\u2019t aiming to study, but that emerge unexpectedly,\u201d he added. \u201cThey push the boundaries of what we think is possible.\u0022 He and assistant professor James Stroud expanded upon this theme in a \u003Ca href=\u0022https:\/\/cos.gatech.edu\/news\/natures-time-machine-how-long-term-studies-unlock-evolutions-secrets\u0022\u003Ereview of long-term experiments in evolutionary biology\u003C\/a\u003E, published in the same issue of \u003Cem\u003ENature\u003C\/em\u003E.\u003C\/p\u003E\u003Cp\u003EThis discovery sheds new light on the evolutionary dynamics of whole-genome duplication and provides a unique opportunity to explore the consequences of such genetic events. With its potential to fuel future discoveries in evolutionary biology, this work represents an important step in understanding how life evolves on both a short-term and long-term scale.\u003C\/p\u003E\u003Cp\u003E\u201cScientific progress is seldom a straightforward journey,\u201d Tong said. \u201cInstead, it unfolds along various interconnected paths, frequently coming together in surprising ways. It\u0027s at these crossroads that the most thrilling discoveries are made.\u201d\u003C\/p\u003E\u003Cp\u003E\u0026nbsp;\u003C\/p\u003E\u003Cp\u003E\u003Cstrong\u003ENote\u003C\/strong\u003E:\u0026nbsp;Ozan Bozdag, Sayantan Datta, Daniella Haas, Saranya Gourisetti, Harley Yopp, Thomas Day,\u0026nbsp;Dung Lac, Peter Conlin, and Ahmad Khalil also played major roles in this experiment.\u0026nbsp;\u003C\/p\u003E\u003Cp\u003E\u003Cstrong\u003EFunding\u003C\/strong\u003E: The U.S. National Institutes of Health (NIH), Human Frontiers Science Program, and the Packard Fellowship for Science and Engineering.\u0026nbsp;\u003C\/p\u003E\u003Cp\u003E\u003Cstrong\u003ECitation\u003C\/strong\u003E: Tong, K., Datta, S., Cheng, V.\u0026nbsp;\u003Cem\u003Eet al.\u003C\/em\u003E\u0026nbsp;Genome duplication in a long-term multicellularity evolution experiment.\u0026nbsp;\u003Cem\u003ENature\u003C\/em\u003E\u0026nbsp;(2025).\u0026nbsp;\u003C\/p\u003E\u003Cp\u003E\u003Cstrong\u003EDOI\u003C\/strong\u003E: https:\/\/doi.org\/10.1038\/s41586-025-08689-6\u003C\/p\u003E\u003Cp\u003E\u0026nbsp;\u003C\/p\u003E","summary":"","format":"limited_html"}],"field_subtitle":"","field_summary":[{"value":"\u003Cp\u003EGeorgia Tech scientists uncovered how whole-genome duplication emerges and remains stable over thousands of generations of evolution in the lab. \u0026nbsp;\u003C\/p\u003E","format":"limited_html"}],"field_summary_sentence":[{"value":"While the researchers initially set out to explore how organisms transition to multicellularity, they discovered something else entirely."}],"uid":"36123","created_gmt":"2025-03-26 18:12:42","changed_gmt":"2025-03-26 18:32:49","author":"Catherine Barzler","boilerplate_text":"","field_publication":"","field_article_url":"","location":"Atlanta, GA","dateline":{"date":"2025-03-26T00:00:00-04:00","iso_date":"2025-03-26T00:00:00-04:00","tz":"America\/New_York"},"extras":[],"hg_media":{"676675":{"id":"676675","type":"image","title":"poster_image.jpg","body":"\u003Cp\u003EEvolved macroscopic \u0022snowflake\u0022 yeast from the MuLTEE experiment. The large size of the nuclei (yellow) and cells (cyan) are results of whole-genome duplication and aneuploidy. Credit: Ratcliff Lab\u003C\/p\u003E","created":"1743009807","gmt_created":"2025-03-26 17:23:27","changed":"1743009807","gmt_changed":"2025-03-26 17:23:27","alt":"Image of yeast cells from the MuLTEE experiment","file":{"fid":"260490","name":"poster_image.jpg","image_path":"\/sites\/default\/files\/2025\/03\/26\/poster_image.jpg","image_full_path":"http:\/\/hg.gatech.edu\/\/sites\/default\/files\/2025\/03\/26\/poster_image.jpg","mime":"image\/jpeg","size":751302,"path_740":"http:\/\/hg.gatech.edu\/sites\/default\/files\/styles\/740xx_scale\/public\/2025\/03\/26\/poster_image.jpg?itok=vH6XJBV6"}},"676676":{"id":"676676","type":"image","title":"sm-cover-nature.jpg","body":"\u003Cp\u003E\u003Cem\u003ENature\u003C\/em\u003E featured Ratcliff and Tong\u0027s paper (and yeast) as the cover story of their March 20 issue. (Credit: Nature)\u003C\/p\u003E","created":"1743010574","gmt_created":"2025-03-26 17:36:14","changed":"1743010574","gmt_changed":"2025-03-26 17:36:14","alt":"Nature magazine cover featuring yellow and cyan yeast cells on a black background","file":{"fid":"260491","name":"sm-cover-nature.jpg","image_path":"\/sites\/default\/files\/2025\/03\/26\/sm-cover-nature.jpg","image_full_path":"http:\/\/hg.gatech.edu\/\/sites\/default\/files\/2025\/03\/26\/sm-cover-nature.jpg","mime":"image\/jpeg","size":644903,"path_740":"http:\/\/hg.gatech.edu\/sites\/default\/files\/styles\/740xx_scale\/public\/2025\/03\/26\/sm-cover-nature.jpg?itok=M4WozyTB"}},"676677":{"id":"676677","type":"image","title":"ratcliff-and-tong.png","body":"\u003Cp\u003EWilliam Ratcliff, professor in the School of Biological Sciences, and Kai Tong, a former Ph.D. student in Ratcliff\u0027s lab who is now a postdoctoral fellow at Boston University\u003C\/p\u003E","created":"1743011923","gmt_created":"2025-03-26 17:58:43","changed":"1743011923","gmt_changed":"2025-03-26 17:58:43","alt":"Will Ratcliff and Kai Tong","file":{"fid":"260493","name":"ratcliff-and-tong.png","image_path":"\/sites\/default\/files\/2025\/03\/26\/ratcliff-and-tong.png","image_full_path":"http:\/\/hg.gatech.edu\/\/sites\/default\/files\/2025\/03\/26\/ratcliff-and-tong.png","mime":"image\/png","size":1546810,"path_740":"http:\/\/hg.gatech.edu\/sites\/default\/files\/styles\/740xx_scale\/public\/2025\/03\/26\/ratcliff-and-tong.png?itok=2FpU-nRI"}},"676678":{"id":"676678","type":"image","title":"vivian and daniella.jpg","body":"\u003Cp\u003EVivian Cheng (left) and Daniella Haas genetically engineered the lab\u0027s tetraploid snowflake yeast when they were undergraduate students at Georgia Tech.\u003C\/p\u003E","created":"1743012092","gmt_created":"2025-03-26 18:01:32","changed":"1743012092","gmt_changed":"2025-03-26 18:01:32","alt":"Vivian Cheng and Daniella Haas","file":{"fid":"260494","name":"Screenshot-2025-03-26-at-1.41.06-PM.jpg","image_path":"\/sites\/default\/files\/2025\/03\/26\/Screenshot-2025-03-26-at-1.41.06-PM.jpg","image_full_path":"http:\/\/hg.gatech.edu\/\/sites\/default\/files\/2025\/03\/26\/Screenshot-2025-03-26-at-1.41.06-PM.jpg","mime":"image\/jpeg","size":347773,"path_740":"http:\/\/hg.gatech.edu\/sites\/default\/files\/styles\/740xx_scale\/public\/2025\/03\/26\/Screenshot-2025-03-26-at-1.41.06-PM.jpg?itok=ZZLjWrki"}},"676681":{"id":"676681","type":"image","title":"harley and saranya.jpg","body":"\u003Cp\u003EGeorgia Tech alums Harley Yopp and Saranya Gourisetti also carried out key research for the project as undergraduates.\u003C\/p\u003E","created":"1743013610","gmt_created":"2025-03-26 18:26:50","changed":"1743013610","gmt_changed":"2025-03-26 18:26:50","alt":"Harley Yopp and Saranya Gourisetti","file":{"fid":"260497","name":"Screenshot-2025-03-26-at-1.41.25-PM.jpg","image_path":"\/sites\/default\/files\/2025\/03\/26\/Screenshot-2025-03-26-at-1.41.25-PM.jpg","image_full_path":"http:\/\/hg.gatech.edu\/\/sites\/default\/files\/2025\/03\/26\/Screenshot-2025-03-26-at-1.41.25-PM.jpg","mime":"image\/jpeg","size":241386,"path_740":"http:\/\/hg.gatech.edu\/sites\/default\/files\/styles\/740xx_scale\/public\/2025\/03\/26\/Screenshot-2025-03-26-at-1.41.25-PM.jpg?itok=7yVBHDUL"}}},"media_ids":["676675","676676","676677","676678","676681"],"related_links":[{"url":"https:\/\/research.gatech.edu\/journey-origins-multicellular-life-long-term-experimental-evolution-lab","title":"A Journey to the Origins of Multicellular Life: Long-Term Experimental Evolution in the Lab"}],"groups":[{"id":"1188","name":"Research Horizons"}],"categories":[],"keywords":[{"id":"187915","name":"go-researchnews"}],"core_research_areas":[],"news_room_topics":[],"event_categories":[],"invited_audience":[],"affiliations":[],"classification":[],"areas_of_expertise":[],"news_and_recent_appearances":[],"phone":[],"contact":[{"value":"\u003Cp\u003ECatherine Barzler, Senior Research Writer\/Editor\u003C\/p\u003E\u003Cp\u003E\u003Ca href=\u0022mailto:catherine.barzler@gatech.edu\u0022\u003Ecatherine.barzler@gatech.edu\u003C\/a\u003E\u003C\/p\u003E","format":"limited_html"}],"email":["catherine.barzler@gatech.edu"],"slides":[],"orientation":[],"userdata":""}}}