Figure 1

Phylogenetic relationships of eight SRs in 12 Drosophila species. This is a corrected distance tree based on aligned amino acids and rooted at the midpoint. The variable length and sequence N-termini upstream of the conserved "pre-peak" region (Figures 7, 8, 9, 10, 11, 12 and 13) were removed from the alignment. Species names are abbreviated to the genus plus the first three letters of the species name, and are color-coded. The eight proteins are indicated on the right. Bootstrap support from 1000 replications of uncorrected distance analysis is shown for the major branches. Most orthologous relationships are in accordance with the known species relationships, or near enough, and bootstrap support is not shown for them. Intron losses are shown in lower case light blue letters above the branches to which they map, but only if not shown in Figure 3.