Figure 2.

Phylogenetic relationships between passerine lineages based on myoglobin intron II and cytochrome b sequences from a total of 84 species (cf. Alström et al., 2006; Supplementary Table S3). Collapsed nodes are shown and numbers are posterior probabilities (for model details, see Materials and Methods). Species included in this study are indicated in bold and common name initials are placed to the right of each respective branch: great reed warbler (GRW), common whitethroat (CW), skylark (SL), goldcrest (GC) and blue tit (BT). Grey circles (in full) highlight branches in which sex linkage of chromosome 4a markers was observed; white circles indicate branches in which representative species showed no sex linkage.