MSGID: 1:317/3 64781f13   
   PID: hpt/lnx 1.9.0-cur 2019-01-08   
   TID: hpt/lnx 1.9.0-cur 2019-01-08   
    Geneticists discover hidden 'whole genome duplication' that may explain   
   why some species survived mass extinctions    
      
     Date:   
         May 31, 2023   
     Source:   
         Trinity College Dublin   
     Summary:   
         Geneticists have unearthed a major event in the ancient history   
         of sturgeons and paddlefish that has significant implications for   
         the way we understand evolution. They have pinpointed a previously   
         hidden 'whole genome duplication' (WGD) in the common ancestor   
         of these species, which seemingly opened the door to genetic   
         variations that may have conferred an advantage around the time   
         of a major mass extinction some 200 million years ago.   
      
      
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   FULL STORY   
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   Geneticists have unearthed a major event in the ancient history of   
   sturgeons and paddlefish that has significant implications for the way   
   we understand evolution. They have pinpointed a previously hidden "whole   
   genome duplication" (WGD) in the common ancestor of these species, which   
   seemingly opened the door to genetic variations that may have conferred   
   an advantage around the time of a major mass extinction some 200 million   
   years ago.   
      
   The big-picture finding suggests that there may be many more overlooked,   
   shared WGDs in other species before periods of extreme environmental   
   upheaval throughout Earth's tumultuous history.   
      
   The research, led by Professor Aoife McLysaght and Dr Anthony Redmond from   
   Trinity College Dublin's School of Genetics and Microbiology, has just   
   been published in leading international journal, Nature Communications.   
      
   Professor Aoife McLysaght said: "Whole genome duplication is exactly   
   as it sounds -- it's a fascinating evolutionary event where an entire   
   genome is copied and pasted so that a species suddenly has twice the   
   genetic material as it did before. Whereas most species, like us, are   
   'diploid' -- having pairs of chromosomes, one from each parent -- after   
   whole genome duplication everything is in four copies. This effectively   
   provides a lot of raw material for mutations -- and evolution -- to   
   occur. Eventually, a species genome will revert to the typical pairs   
   through a process called rediploidisation.   
      
   "We've know about whole genome duplication and rediploidisation for a   
   long time but what is new, and exciting, is that we have shown that the   
   time it takes for the second part of the process to complete is very   
   important. In this case, it took a long, long time -- so long that some   
   gene duplications appear to be species-specific, occurring after the   
   two species went their separate ways on the tree of life.   
      
   "As a result, the ancient original whole genome duplication that happened   
   before the species had separated had been missed until now. We believe the   
   same thing might have happened in many other species lineages and that   
   is important given the possibility that it generated genomic conditions   
   that helped the species survive mass extinctions."  Genetically,   
   sturgeons and paddlefish show evidence of shared and non-shared gene   
   duplications that were themselves derived from the ancient WGD, which,   
   when timestamped to just over 250 million years ago places it just before   
   the Permian-Triassic mass extinction that wiped out over half of the   
   families of all living things.   
      
   This would seem to add more weight to the theory that WGD events provide   
   species with more of an evolutionary canvas to work with; more genetic   
   material means more capacity for variations over a given time, and that   
   in turn increases the chance of some conferring an advantage to cope with   
   difficult or changing environmental conditions. These would certainly have   
   been in evidence during the period of rediploidisation that overlapped   
   with the Triassic- Jurassic mass extinction around 200 million years ago.   
      
   Dr Anthony Redmond said: "Multiple whole genome duplication events   
   famously occurred in our ancient early vertebrate ancestors and these   
   have shaped the landscape of our modern human genome.   
      
   "Our findings are exciting because as well as shining a light on sturgeon   
   and paddlefish genome evolution, they provide a comparative snapshot of   
   how our early vertebrate ancestors genome and duplicated genes evolved   
   after these doubling events."   
       * RELATED_TOPICS   
             o Plants_&_Animals   
                   # Extinction # Evolutionary_Biology # New_Species   
             o Earth_&_Climate   
                   # Exotic_Species # Environmental_Policy #   
                   Environmental_Awareness   
             o Fossils_&_Ruins   
                   # Evolution # Fossils # Early_Humans   
       * RELATED_TERMS   
             o Extinction_event o Permian-Triassic_extinction_event o   
             Toba_catastrophe_theory o Timeline_of_evolution o Dinosaur   
             o Cretaceous-Tertiary_extinction_event o Jurassic o   
             Timeline_of_human_evolution   
      
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   Story Source: Materials provided by Trinity_College_Dublin. Note:   
   Content may be edited for style and length.   
      
      
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   Journal Reference:   
      1. Anthony K. Redmond, Dearbhaile Casey, Manu Kumar Gundappa, Daniel J.   
      
         Macqueen, Aoife McLysaght. Independent rediploidization masks shared   
         whole genome duplication in the sturgeon-paddlefish ancestor. Nature   
         Communications, 2023; 14 (1) DOI: 10.1038/s41467-023-38714-z   
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   Link to news story:   
   https://www.sciencedaily.com/releases/2023/05/230531150053.htm   
      
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