中国对虾近交两代的DNA随机扩增多态性及其遗传规律分析

The segregation patterns of RAPD markers in the F2 progenies of Chinese fleshy shrimp, Fenneropenaeus chinensis

  • 摘要: 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。

     

    Abstract: 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 non-segregating 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 1:1ratio, the former accounted for 14.7% of all segregated markers respectively and the latter accounted for 64.7%. 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, had not be conjectured their genotypic combinations, which were segregated 1:1 ratio in the F2 progenies. Non-standard Mendelian segregating marks and abnormal segregating marks accounted respectively for 11.7% and 8.9% of all segregated markers respectively. Totally, 76.5% segregating markers, explained by two way pseudo-testcross, 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.

     

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