Supplemental Information is Open Access at G3:Summary PDF and LegendsFig S1. Multiple sequence alignment of centromere (pdf)Table S2. GOB-HMM families detected in representative strains of five Saccharomyces species (pdf)Dataset 1. Likelihood-ratio tests for variation in selection pressure (xls)Dataset 2. Complete lists of candidate gene gains and losses detected by computational screens (xls)Table S1. Genes orthologous among representative strains of five Saccharomyces sensu stricto yeast species (xls)Table S3. tRNA gene content (xls)