Figure 1.

Gene map of L. forficatus mtDNA. Protein and rRNA genes are abbreviated as follows: atp6 and atp8 (genes for subunits 6 and 8 of the F₀ ATPase), cox1–cox3 (genes for cytochrome c oxidase subunits 1–3), cob (gene for apocytochrome b), nad1–nad6 and nad4L (genes for NADH dehydrogenase subunits 1–6 and 4L), and rrnS and rrnL (genes for small and large subunit rRNAs). The 22 tRNA genes are identified by the one-letter code for the corresponding amino acid. Two leucine and two serine tRNA genes are differentiated by their anticodon sequence with trnL(uag) marked as L1, trnL(uaa) as L2, trnS(ucu) as S1, and trnS(uga) as S2. The direction of transcription for each gene is shown by an arrow. trnI (shaded area) is the only gene translocated relative to the arthropod primitive gene arrangement exemplified by the mtDNA of the horseshoe crab Limulus polyphemus (10). The numerals near each tRNA gene indicate the number of mismatches in the acceptor stems inferred from mtDNA sequence.