Comparison of the α-β globin genes in the MC and LA loci of diverse teleosts. Linkage between globin genes is represented by solid line (broken line indicates uncertainty). The genes are transcribed in the rightward (upper) or leftward (lower) direction. The linkage groups are numbered. The number of paired α-β genes in salmon is unknown (n). The estimated divergence times (MYA) are based on mitochondrial DNA sequences .