Artificial Induction Of Diploid Gynogenesis In Nibea Albiflora And Preliminary Evidence For The Sex Determination

In the present study, Nibea albiflora is the research object, adopting homologoussperm induced diploid gynogenesis in Nibea albiflora, The offspring of gynogenesis wasidentificated by using morphology, flow cytometry instrument and microsatellitetechnology.At the same time, Exploring the conditions that heterologous sperm inducedgynogenesis in Nibea albiflora, Finally, growth characteristics and mechanism of sexdetermination of gynogenesis offspring has carried on the preliminary discussion,Researchpurpose is to provide important technical means and scientific basis for Geneticimprovement.The main results were shown as follows:1. The induction of diploid gynogenesis in Nibea albiflora was established using acombination of UV-irradiated homologous sperm and cold shock of the resulting embryo toinhibit the second meiotic division. The optimal UV irradiation of the N. albiflora sperm forgynogenesis was420mJ/cm2. A typical “Hertwig effect” was observed based on thefertilization, hatching and occurrence of haploid by subjecting eggs fertilized withUV-irradiation sperm. Treatment optima for diploid gynogenesis were3℃for8min at2min after fertilization based on several experiments. Results obtained from the observationsof external morphologies and detection of DNA content in larvae by flow cytometry provedthat the larvae were diploid gynogenesis. Furthermore, genetic inheritance from the parentsto the progeny was examined by microsatellite loci. The genetic analysis revealedexclusively maternal inheritance in all gynogenetic fry and no paternal contributions weredetected. The offspring showed high genetic homogeneity with their female parent.2. The heterologous sperm induced Nibea albiflora gynogenesis was conducted apreliminary exploration.Selection of Oplegnathus fasciatus sperm as a heterologous sperm,destroyed the genetic material of Oplegnathus fasciatus sperm live by ultraviolet irradiation,after the completion of the work, the sperm of Oplegnathus fasciatus and egg of Nibeaalbiflora started artificial insemination, which obtained gynogenetic haploid, haploid eggsby the cold shock to achieved double recovery, successfully obtained Nibea albiflorafemale the gynogenetic diploid fish fry in the end. However,the induction rate is very low.3. The mechanism of growth characteristics and sex determination of Nibea albifloragynogenetic offspring are discussed.The researchers measured the gynogenetic Nibeaalbiflora total length, body length and body weight, understanding the cultural ecologicalcharacters of Nibea albiflora gynogenetic offspring.At the same time, gynogenesis Nibeaalbiflora and normal control group of Nibea albiflora were dissected and the gonad of cultivation to November age, fixed in Bouin’s fluid, sex identification methods usingconventional histological sections.The results showed that: the sex ratio of the ordinaryNibea albiflora is close to the theoretical value of1:1, no significant difference (P>0.05);while in random anatomical80tail November age gynogenetic offspring of Nibea albiflora,female percentage is97.5%, ovary is at stage III, the third phase oocytes the parent cells.The preliminary conclusion of sex determining mechanisms of Nibea albiflora is of typeXX/XY.