Evolutionary relationships among vertebrate β-like globin genes analysed by maximum parsimony (MP) trees of length 926 (one of eight trees). Third position in codons were excluded in the MP analyses, which were conducted using a heuristic search in PAUP* v.4.0b10 . The tree is rooted using pufferfish β-globin. Numbers adjacent to branches represent % bootstrap values (>50%) from MP heuristic analyses of 1000 pseudoreplicates. Accession numbers for sequences are given in the caption of Figure 3.