After the duplication: Gene loss and adaptation in Saccharomyces genomes

The ancient duplication of the Saccharomyces cerevisiae genome and subsequent massive loss of duplicated genes is apparent Mien it is compared to the genomes of related species that diverged before the duplication event. To learn more about the evolutionary effects of the duplication event, we compared the S. cerevisiae genome to other Saccharomyces genomes. We demonstrate that the whole genome duplication occurred before S. castellii diverged front S. cerevisiae. hi addition to more accurately dating the duplication event, this finding allowed Its to study the effects of the duplication on two separate lineages. Analyses of the duplication regions of the genomes indicate that most of the duplicated genes (similar to 85%) were lost before the speciatiori. Only a small amount of paralogous gene loss (4-6%) occurred after speciatiori. On the other hand, S. castellii appears to have lost several hundred genes that were not retained as duplicated paralogs. These losses could be related to genomic rearrangements that reduced the number of chromosomes front 16 to 9. In addition to S. castellii, other Saccharomyces sensu lato species likely diverged front S. cerevisiae after the duplication. A thorough analysis of these species will likely reveal other important outcomes of the whole genome duplication.