| Artificially induced gynogenesis refers to the development of eggs activated bymeans of physical, chemical or biological treatment. All genetic information of thegynogentic embryos is inherited from the female parent. As a way of getting rapidproduction of inbred lines, gynogenesis shows great potential in genetic improvementand the breeding of new varieties. In addition, it is also a useful material in manygenetic researches including sex determination, gene-centromere recombination, genemapping. In this study, parameters for sperm inactivation in Zhikong scallop, Chlamysfarreri were optimized. Single gynogenetic embryo was then picked out for wholegenome amplification (WGA) and single nucleotide polymorphisms (SNP) markerswere used to evaluate the genetic composition for each amplified DNA product. Theresults obtained in this study are summarized as follows:1. Effects of ultraviolet (UV) irradiation on genetical inactivation of sperm wereexamined in C. farreri. UV irradiation of sperm for50s at the intensity of800μW·cm-2·s-1was the optimum parameter to achieve haploid gynogenesis. The haploidrate of embryo was82.5%according to the flow cytometry analysis. The embryosurvival rate decreased with the increasing of irradiation time, while it becameimproved at UV exposure between20s and40s, suggesting the presence of―HertwigEffect‖in the gynogenesis of C. farreri.2. The gynogentic embryos contained enough cells for whole genome amplification.Single embryo was then picked out for WGA.The yield of WGA-DNA was about25μg. SNP markers were used to evaluate the genetic composition for each WGADNA product. The genotyping call rate in WGA-DNA from single embryo was (96.271.50)%, of which (99.030.31)%showed genotyping results consistant with thecontrol.3. A total of96SNPs were selected for genotyping in gynogenetic embryos. As aresult, the homozygous ratios of embryos were between96.88%and91.67%, with an average of (94.81±1.56)%，which was significantly higher than that of their femaleparents (t-test, P<0.05). At the same time, the segregation pattern of32SNP markerswas investigated in the gynogenetic family GF5. It suggested that24of them wereconsistant with the expected ratio (1:1) according to Mendel‘s law while the other8loci were not (χ2test, P<0.05). |
