Partial sequence of the mitochondrial genome of the crustacean Daphnia pulex

A 4062-nucleotide (nt) fragment of the mitochondrial genome of the crustacean Daphnia pulex was sequenced and found to contain the complete genes for eight tRNAs and five proteins (ATP6, ATP8, COII, COIII, ND3) and the partial sequence of COI. In combination with data described previously, approximately 50% of the D. pulex mitochondrial genome has been sequenced. The gene order in this half of the genome is identical to that of Drosophila yakuba which differs from that of the other completely sequenced crustacean mitochondrial genome, Artemia franciscana. Comparison of seven mitochondrial proteins among D. pulex, A. franciscana, D. yakuba, Anopheles gambiae, Locusta migratoria and Apis mellifera a showed that, with one exception, the D. pulex proteins are most similar in length and sequence to the proteins of the dipteran insects. Conversely, patterns of nucleotide bias at third codon positions in fourfold degenerate codon families are very similar in the two crustaceans but differed substantially from the insects.