Publication Date:
2009-10-20
Description:
The relationship between rates of genomic evolution and organismal adaptation remains uncertain, despite considerable interest. The feasibility of obtaining genome sequences from experimentally evolving populations offers the opportunity to investigate this relationship with new precision. Here we sequence genomes sampled through 40,000 generations from a laboratory population of Escherichia coli. Although adaptation decelerated sharply, genomic evolution was nearly constant for 20,000 generations. Such clock-like regularity is usually viewed as the signature of neutral evolution, but several lines of evidence indicate that almost all of these mutations were beneficial. This same population later evolved an elevated mutation rate and accumulated hundreds of additional mutations dominated by a neutral signature. Thus, the coupling between genomic and adaptive evolution is complex and can be counterintuitive even in a constant environment. In particular, beneficial substitutions were surprisingly uniform over time, whereas neutral substitutions were highly variable.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Barrick, Jeffrey E -- Yu, Dong Su -- Yoon, Sung Ho -- Jeong, Haeyoung -- Oh, Tae Kwang -- Schneider, Dominique -- Lenski, Richard E -- Kim, Jihyun F -- England -- Nature. 2009 Oct 29;461(7268):1243-7. doi: 10.1038/nature08480. Epub 2009 Oct 18.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, Michigan 48824, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/19838166" target="_blank"〉PubMed〈/a〉
Keywords:
*Adaptation, Physiological
;
DNA Mutational Analysis
;
Escherichia coli/*genetics/growth & development
;
*Evolution, Molecular
;
Genetic Fitness
;
Genome, Bacterial/*genetics
;
Models, Genetic
;
Mutation
;
Selection, Genetic
;
Time Factors
Print ISSN:
0028-0836
Electronic ISSN:
1476-4687
Topics:
Biology
,
Chemistry and Pharmacology
,
Medicine
,
Natural Sciences in General
,
Physics
Permalink
