An association between head-spot types and genetic types in char distributed in the Chugoku region, Japan

Abstract

Char samples distributed in rivers originating from the Chugoku Mountain Chain, Japan, were collected, identified to two subspecies; Gogi and Nikkoiwana. They were categorized into 8 head-spot types by morphology, and into genetic haplotypes based on DNA sequences of the Cyt.b region of mtDNA. A genetic tree was constructed based on the sequences. In addition, head-spot types were categorized by haplotype composition. Spot types A and D were observed only in Gogi. Type B was dominated in Gogi whereas type H dominated in Nikkoiwana. Eight haplotypes were found only in Gogi whereas only one haplotype was found only in Nikkoiwana. Six haplotypes were observed in both subspecies. In addition, most of the haplotypes related distantly to ancestral ones were observed only in Gogi. Based on haplotype composition similarity, spot types were largely categorized into 3 groups: F and G; B, C, E and H; A and D. Spot types C and E constructed an additional small cluster. These results suggest that there are no clear genetic separation between Gogi and Nikkoiwana, Gogi is likely to have been more deeply differentiated than Nikkoiwana, and wide spot types are likely to have been genetically isolated from narrow types.