Observed numbers of gene families with one or more duplications after the last common ancestor of Schizosaccharomyces pombe andSaccharomyces cerevisiae, illustrating the numbers of families duplicated in each species separately and in both species. Separate analyses were observed for a data set of all proteins (650 families) and for a data set excluding ribosomal proteins (623 families). Observed numbers were compared with expected numbers, calculated by multiplying the proportions of families with one or more duplications in S. pombe by the proportion of families with one or more duplications in S. cerevisiae. For both data sets the observed and expected numbers were significantly different (χ2 = 117.2 and 82.3, respectively;P < 0.00001 in both cases).
