【摘要】 用紫外线灭活栉孔扇贝精子和6-DMAP处理受精卵抑制第二极体,获得A、B、C 3组雌核发育栉孔扇贝。采用筛选获得的5对多态性微卫星引物对3个家系雌核发育组30个个体、双亲及对照组40个个体进行了遗传变异分析。结果显示:3个家系雌核发育组后代中均有部分个体出现父本基因,表明精子遗传物质失活不彻底,雌核发育组中存在正常受精个体;在具多态性的5个基因座位上均发生了基因-着丝点之间的重组,重组率在26.7%—55.0%之间,表明通过抑制第二极体排出获得的栉孔扇贝雌核发育后代在个体和群体水平上具有一定的基因杂合;3个家系后代的平均基因纯合率为59.1%,而其对照组家系为2.5%,雌核发育使基因的纯合率提高了56.6%。研究表明雌核发育是促进基因纯合的一个有效途径,微卫星标记技术是贝类雌核发育鉴定和遗传分析的有效方法。更多还原

【Abstract】 Zhikong scallop,Chlamys farreri,which is widely distributed along the coasts of North China,Korea,Japan and Eastern Russia,is one of the commercially important fishery and aquaculture species in China.Compared with classical genetic methods,artificial gynogenesis has proved to be a valuable genetic tool for the rapid production of inbred lines,development of all-female populations as well as for gene mapping.Microsatellite recently has become an extremely popular marker in a wide variety of its genetic investigation.We used the genotyping data of five microsatellite loci to check the absence of any paternal contribution to the gynogenetic offspring genome,to estimate the M-C recombination rate and to analyze the homozygous ratio in the induced gynogenetic diploids.In this research,gynogenetic diploid Chlamys farreri were induced by inhibiting exclusion of the second polar body with 6-DMAP in eggs fertilized with UV irradiated sperm.Five polymorphism microsatellite markers were used to detect the genetic variations of 30 larvae in the gynogenetic families A,B and C,40 larvae in their control groups and their parents.Two of the five microsatellite loci showed the existence of null alleles in two control groups.In the 15 genotypic ratios observed(3 families×5 loci),13 genotypic ratios were in accordance with Mendelian expectations(p>0.122).The remaining two genotypic ratios in family B at CFMSM020 and family C at CFMSM009 conformed to Mendelian expectations when null alleles were considered.The presence of null alleles was the major problem of microsatellite markers for population genetics studies in the Chlamys farreri.The results of the five microsatellite analyses revealed the presence of male DNA in the three gynogenetic families,indicating they all derived from normal fertilization.6-DMAP treatment produced 70.2% gynogenetic diploids.Recombination was observed at the five polymorphic loci and the recombination rates between microsatellite locus and centromere ranged from 26.7% to 55.0%(48.8% mean).The observed Recombination rates were often lower than the theoretical maximum 67.0%.These results indicated that there was higher heterozygosity in the first meiogynogenetic generation of scallop,Chlamys farreri.The production of gynogenetic diploids provided a new way for genetic improvement of scallop culture and to get well-bred species.The homozygosity ratio of the offspring from the three families were 64.0%,56.3%,57.1%,respectively and the average homozygous ratio was 59.1% while that of the control groups were 2.5%.The homozygous ratio was increased 56.6% by gynogenesis.This study shows that gynogenesis is an effective method to promote gene purification.Induced diploid gynogenesis has been recognized as a potential method to produce inbred line of Chlamys farreri rapidly.In addition,microsatellite analysis is an effective method for the verification of gynogenesis because of their codominant and highly polymorphic nature.更多还原