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Chromosomal evolution in Saccharomyces.

TitleChromosomal evolution in Saccharomyces.
Publication TypeJournal Article
Year of Publication2000
AuthorsFischer, G, James, SA, Roberts, IN, Oliver, SG, Louis, EJ
Date Published2000 May 25
KeywordsChromosomes, Fungal, DNA Transposable Elements, Evolution, Molecular, Phylogeny, Recombination, Genetic, Saccharomyces, Translocation, Genetic

The chromosomal speciation model invokes chromosomal rearrangements as the primary cause of reproductive isolation. In a heterozygous carrier, chromosomes bearing reciprocal translocations mis-segregate at meiosis, resulting in reduced fertility or complete sterility. Thus, chromosomal rearrangements act as a post-zygotic isolating mechanism. Reproductive isolation in yeast is due to post-zygotic barriers, as many species mate successfully but the hybrids are sterile. Reciprocal translocations are thought to be the main form of large-scale rearrangement since the hypothesized duplication of the whole yeast genome 10(8) years ago. To test the chromosomal speciation model in yeast, we have characterized chromosomal translocations among the genomes of six closely related species in the Saccharomyces 'sensu stricto' complex. Here we show that rearrangements have occurred between closely related species, whereas more distant ones have colinear genomes. Thus, chromosomal rearrangements are not a prerequisite for speciation in yeast and the rate of formation of translocations is not constant. These rearrangements appear to result from ectopic recombination between Ty elements or other repeated sequences.

Alternate JournalNature
PubMed ID10839539

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