Identification of Chub and Spotted Mackerels with Mitochondorial Cytochrome b Gene and Its Application to Respective Pelagic Eggs Fixed with Formalin

Abstract

Mitochondrial cytochrome b genes were amplified by PCR using the total DNA as a template from muscle tissues of adult chub mackerel Scomber japonicus and spotted mackerel S. australasicus, and their nucleotide sequences determined. The full length of the cytochrome b gene consisted of 1, 140 nucleotides irrespective of the two species, where 16 species-specific variations were observed. Among various restriction enzymes which recognize the cytochrome b genes from the two fish species, MvaI was specific to the gene of S. japonicus and MboI to that of S. australasicus, with both enzymes producing two fragments. Such species-specific fragmentation patterns were applicable to identification of formalin-fixed pelagic eggs from the two species, which was impossible with morphological characteristics.