Correlation between age and “essentiability” of the S. pombe genes. (A) A simplified phylogenetic tree of the eukaryotic kingdom (Sipiczki 2000) is given. The arrows indicate the point of appearance of S. pombe class Ib, Id, III, and V genes on the tree. (B) Additional S. pombe genes from class Id and class III were deleted using the procedure described in Methods. The phenotype of the deletion is given in the third column. The deletion phenotype of the S. cerevisiae closest homolog of each S. pombe gene is given in the last column. (C) Lethality in gene classes Ib, Id, III, and V of S. pombe andS. cerevisiae is compared. Intervals of confidence (P90) are given for each class of genes.
