中国对虾连续两代的DNA随机扩增多态性及其遗传规律分析

The segregation patterns of RAPD markers in the F_2 progenies of Chinese fleshy shrimp,Fenneropenaeus chinensis

为评估DNA随机扩增多态性标记在中国对虾遗传连锁图谱构建中的应用前景,利用中国对虾单对交配亲本及其子二代材料,对RAPD标记及其遗传规律进行了研究。22条RAPD随机引物扩增结果的统计分析表明,标记在中国对虾F2的遗传规律可归为不分离标记和分离标记:不分离标记,指在亲本和后代中均不分离的标记,占总位点的54.1%;分离标记占总位点的45.9%。其中,分离标记又包括符合孟德尔遗传分离的标记、偏离孟德尔遗传分离标记和异常分离标记。符合孟德尔分离的标记中,分离比例为3∶1的标记占分离标记的14.7%;总的1∶1标记占分离标记的64.7%;偏离孟德尔分离和异常分离的标记分别占分离标记的11.7%和8.9%。在这些分离的标记中,有76.5%的位点在"双假测交理论"的策略中适合构建中国对虾的遗传连锁图谱,这为以中国对虾F2为作图群体,并利用RAPD标记构建中国对虾遗传连锁图谱提供了理论支持。

The genetic structure and segregation of molecular markers in F2 of Chinese shrimp （Fenneropenaeus, chinensis） were studied by random amplified polymorphic DNA （RAPD） technology to explore its usefulness in linkage mapping construction. Two hereditable types of DNA markers, the nonsegregating type and segregating type, were identified from the amplification results of 22 random primers. The non-segregating marks in both parents and progenies accounted for 54.1% of all markers, reflecting one genotypic combinations of G♀ and G♂（AA × AA）. There were three kinds of segregation, including Mendelian segregation, deviated segregation and abnormal segregation, which accounted for 45.9% of all marks. The standard Mendelian segregating markers were divided in 3 ： 1 ratio and 1 ： l ratio, the former accounted for 14.7% of all segregated markers and the latter accounted for 64.7% respectively. The 3 ： 1- segregated markers in the F2 represented four genotypic combinations of G♀ and G♂ （AA × aa,Aa × aa、Aa × Aa and Aa × AA）, and one genotypic combinations of F1♀ and F1♂ （ Aa × Aa） ; the 1 ： 1-segregated markers in the F2 represented two genotypic combinations of G♀ and G♂ （Aa × aa and Aa × Aa）, and one genotypic combinations of F1♀ and F1♂ （Aa × aa）; non-parental heteroduplex, so far, has not be conjectured their genotypic combinations, which were segregated 1 ： 1 ratio in the F2 progenies. Nonstandard Mendelian segregating marks and abnormal segregating marks accounted for 11.7% and 8.9% of all segregated markers respectively. Totally, 76.5% segregating markers, explained by two way pseudotestcross, could be used to construct genetic maps of F. chinensis. Accordingly, the result would lay a theoretical basis for genetic linkage map construction using RAPD markers and F2 population.