PARTIAL MITOCHONDRIAL-DNA SEQUENCE OF THE CRUSTACEAN DAPHNIA-PULEX

A 3667-base pair (bp) fragment of the mitochondrial genome of the crus tacean Daphnia pulex has been sequenced and found to contain the compl ete genes for the small subunit ribosomal RNA, ND2, seven tRNAs and th e control region. This organization is identical to that found in Dros ophila yakuba mtDNA yet D. pulex mtDNA exhibits several unique feature s when compared to other mitochondrial sequences. The sequenced fragme nt is only 62.6% A + T which is much lower than that of any other arth ropod mtDNA sequenced to date. D. pulex mtDNA also exhibits length con servation having shorter coding and non-coding regions. The putative c ontrol region is 689 bp in length and includes a sequence that has the potential to fold into a hairpin structure with a perfect 20-bp pair stem and a 22-base loop.