Proportion of Essential Genes within Conserved Synteny Blocks

(A) The black bar represents the proportion of essential genes in the genome of S. cerevisiae (Sc), as defined in the Comprehensive Yeast Genome Database (http://mips.gsf.de/genre/proj/yeast). The relative proportions of orthologs to these genes among the total number of genes comprised within the syntenic blocks with the genomes of C. glabrata (Cg), K. lactis (Kl), D. hansenii (Dh), and Y. lipolytica (Yl) are represented by dark gray bars. Proportions of essential genes concomitantly conserved within synteny blocks in three, four, and five species are indicated by light gray bars. Error bars represent two standard deviations, and the number of genes considered in each case is indicated in parentheses.

(B) Comparison of the proportions of essential genes among syntenic orthologs and among all orthologs at increasing phylogenetic distances. Phylogenetic distances between S. cerevisiae and C. glabrata, S. cerevisiae and K. lactis, S. cerevisiae and D. hansenii, and S. cerevisiae and Y. lipolytica are reported on the x-axis.