Discovery of a male-biased mutant family and identification of a male-specific SCAR marker in gynogenetic gibel carp Carassius auratus gibelio

<正>Gibel carp(Carassius auratus gibelio) is a uniquely gynogenetic species with a minor ratio of males in natural habitats,but its male origin and sex determination mechanisms have been unknown.In this study,a male-biased mutant family was discovered from the gynogenetic gibel carp,and a male-specific SCAR marker was identified from the mutant family.Normal spermatogenesis was observed in the male testes by immunofluorescence histochemistry.Nearly identical AFLP profiles were observed between males and females,but a male-specific 86 bp AFLP fragment was screened by sex-pool bulked segregant analysis and individual screening.Based on the male-specific AFLP fragment, a total of 579 bp sequences were cloned by genome walking.Subsequently,a male-specific SCAR marker was designed,and the malespecific DNA fragment was confirmed to be steadily transmitted to the next generation and consistently detected only in males.