The cytochrome b and ATPase genes of honeybee mitochondrial DNA

The gene sequences for honeybee cytochrome b, ATPase 6, and ATPase 8 are presented, along with the inferred amino acid sequences of the proteins. These mitochondrial genes are in the same relative positions as are their counterparts in Drosophila mitochondrial mtDNA and have evolved at a significantly greater overall rate than have those of Drosophila. Comparisons using both amino acid identity and the proportion of conservative replacements between the inferred Apis and vertebrate cytochrome b sequences shows the two highly conserved sections reported by Howell, but his recognition of five conserved regions is not well supported. A very high AT bias is reflected in very high codon biases. The best predictors of the number of occurrences of an amino acid in honeybee cytochrome b are the T and G contents of its codon family--unlike the case for vertebrate cytochrome b, in which the codon family size and AT bias are the strongest predictors; protein function, at least as judged by hydrophilicity characteristics, appears to be unaffected by these differing influences on amino acid composition.