Genetic,gonadal development and shape characteristics researches of gynogenetic orange ornamental carp(Cyprinus carpio L.)

Abstract

Gynogenetic orange ornamental carp(Cyprinus carpio L.,Koi)with high hatch rate and survival rate was obtained by egg activation using the UV-inactivated sperm from blunt snout bream(Megalobrama amblycephala) and then chromosomes doubling with cold shock treatment at the temperture of 4 ℃ for 30 min.The gynogenetic orange ornamental carp was proved to be diploid with 100 chromosomes by chromosome number detection and karyotype analysis.At the age of 1 year,10 gynogenetic fish were randomly sampled to detect gonad development and only ovary was observed in all the samples;during the spawning season at the age of 2 years,100 gynogenetic fish were stripped for semen production but none of the samples could strip out semen but green eggs,the presence of all-female gyongenetic orange ornamental carp provided vital evidence to prove that the sex determination type of female orange ornamental carp is XX.In addition,the genetic relationship of SOX gene,the phenotypes and body color between gyongenetic orange ornamental carp and its parent were also observed in this study,and the results show that gyongenetic orange ornamental carp inherits the same amplified fragments as the maternal parent,which provides importment evidence to get rid of its heterozygosity.Meanwhile,gynogenetic orange ornamental carp inherited the graceful shape of its maternal parent and the body color is brighter.The formation of gynogenetic orange ornamental carp lays foundation for purification,rejuvenation and genetic improvement for orange ornamental carp and also provided good material for fish sex determination and sex control research.