Exploring Genome Plasticity and Adaptive Evolution in de novo Hybrid Yeast Species.
Barbara Dunn (1), Gianni Liti (2), Edward J. Louis (2), Frank Rosenzweig (3), Gavin Sherlock (1)
(1) Dept. of Genetics, Stanford University Med. Sch., 300 Pasteur Ave, Stanford, CA, 94305-5120, USA;
(2) Dept. of Genetics, University of Leicester, LE1 7RH Leicester UK;
(3) Divn. of Biological Sciences, Univ. of Montana, Missoula, MT 59812
Genome rearrangements have been implicated as a driving mechanism in the speciation of many organisms, as well as in the progression of cancers and various human aneuploidy syndromes. Using microarray-based Comparative Genomic Hybridization (array-CGH), we have tracked, on a whole-genome scale, the chromosomal rearrangements that occur in the S. cerevisiae genome during the initial steps of de novo speciation in hybrid yeasts formed between Saccharomyces cerevisiae and other sequenced Saccharomyces sensu stricto species. We have found that extensive whole-chromosome aneuploidy, sometimes involving as many as half of the S. cerevisiae chromosomes, is the major type of chromosomal change seen during the early stages of hybrid speciation. We will also monitor genome rearrangements that occur in these newly-formed species during adaptive evolution as they are grown for many generations in chemostats under various stress conditions. These studies represent the first genome-wide assessment of the extent and types of genome rearrangements that occur during real-time speciation.
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