Mechanisms of Chromosome Number Evolution in Yeast
Citation:
Jonathan L. Gordon, Kevin P. Byrne, Kenneth H. Wolfe, Mechanisms of Chromosome Number Evolution in Yeast, PLoS Genetics, 7, 7, e1002190, 2011Download Item:
Abstract:
The whole-genome duplication (WGD) that occurred during yeast evolution changed the basal number of chromosomes from 8 to 16. However, the number of chromosomes in post-WGD species now ranges between 10 and 16, and the number in non-WGD species (Zygosaccharomyces, Kluyveromyces, Lachancea, and Ashbya) ranges between 6 and 8. To study the mechanism by which chromosome number changes, we traced the ancestry of centromeres and telomeres in each species. We observe only two mechanisms by which the number of chromosomes has decreased, as indicated by the loss of a centromere. The most frequent mechanism, seen 8 times, is telomere-to-telomere fusion between two chromosomes with the concomitant death of one centromere. The other mechanism, seen once, involves the breakage of a chromosome at its centromere, followed by the fusion of the two arms to the telomeres of two other chromosomes. The only mechanism by which chromosome number has increased in these species is WGD. Translocations and inversions have cycled telomere locations, internalizing some previously telomeric genes and creating novel telomeric locations. Comparison of centromere structures shows that the length of the CDEII region is variable between species but uniform within species. We trace the complete rearrangement history of the Lachancea kluyveri genome since its common ancestor with Saccharomyces and propose that its exceptionally low level of rearrangement is a consequence of the loss of the non-homologous end joining (NHEJ) DNA repair pathway in this species.
Sponsor
Grant Number
Science Foundation Ireland
07/IN1/B911
Author's Homepage:
http://people.tcd.ie/khwolfehttp://people.tcd.ie/byrneke
Description:
PUBLISHED
Author: BYRNE, KEVIN PATRICK; WOLFE, KENNETH
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PLoSType of material:
Journal ArticleCollections
Series/Report no:
PLoS Genetics;7;
7, e1002190;
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Full text availableKeywords:
Genetics, whole-genome duplication (WGD), yeastMetadata
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