Figure 2
From: Complete mitochondrial genome sequence of Urechis caupo, a representative of the phylum Echiura
A greatly abbreviated schematic of the sequence of Urechis caupo mtDNA. In the interest of brevity, the middle portion of each large gene is omitted and replaced by a numeral indicating the number of nucleotides removed. Since all mitochondrial proteins are thought to initiate with formyl-methionine, an M is placed in parentheses at the first codon position of cox1 (GTG) and nad3 (ATC) to indicate nonconformity to the genetic code. Asterisks indicate inferred stop codons whether complete or abbreviated and plus symbols mark nucleotides that would form the first in frame, complete stop codon if genes instead overlap.