Figure 4

Phylogenetic analysis of A. gossypii DS block 13. A. Three chromosomal segments homologous to this syntenic region and derived from the phylogenetic reconstruction exercise described in Figure 3 were found to be ancestral to A. gossypii, S. cerevisiae, and K. waltii. They are labeled with greek letters. The arrangement of genes in A. gossypii DS block 13 was transformed into the three ancestral chromosomal segments and these were then transformed into corresponding chromosomal segments in S. cerevisiae, invoking both the WGD and PGD evolutionary scenarios. Under WGD, deletions were those that produced the most parsimonious scenario. The minimum number of deletions needed to produce a DS pattern in S. cerevisiae was considered to be 1, and not 3, because there was no guarantee that three chromosomal segments were not part of a single chromosome. B. Because under the WGD scenario we first duplicate the entire gene complement and then proceed to delete and rearrange genes, direction of change in lineages is important. The figure shows alternative WGD reconstructions used to select the most parsimonious WGD scenarios shown in A.