细胞质在玉米配子和合子生活力选择中的作用研究报告

徐辰武

摘 要：偏分离是指观察到的基因型比例偏离预期的孟德尔频率的分离方式，被逐渐认为是一种重要的进化动力，偏分离的主要原因是由生存力位点造成的配子和合子的生存力差异。然而，母体细胞质也可能参与配子和受精卵的生存力选择。该文的目的是定位玉米中的偏分离位点（SDL）并检验配子和合子的生存力是否与母体细胞质环境相关。在该研究中，以正反交构建的F2代分离群体为材料，构建了126个微卫星标记的遗传连锁图，并利用全基因组扫描检测不同母体细胞下分离群体的SDL，在供试的F2群体中共检测到14个显著的SDL。有趣的是，笔者发现在两个不同母体胞质背景下，SDL中的基因型频率发生了明显变化，这表明在不同的细胞质环境下，配子和合子的的生存力发生了变化。此外，JB细胞质背景下，大多数检测到的SDL和偏分离标记均偏向Y53，结果表明细胞质通过影响配子和合子的生存力选择，在F2代群体的偏分离模式中起了重要的作用。

关键词：偏分离 细胞质 选择 生活力 玉米

The Maternal Cytoplasmic Environment May Be Involved in the Viability Selection of Gametes and Zygotes

Xu Chenwu

（Yangzhou University）

Abstract：Segregation distortion is the phenomenon whereby the observed genotypic frequencies of a locus fall outside the expectedMendelian segregation ratio， and it is increasingly recognised as a potentially powerful evolutionary force. The main reason forsegregation distortion is a difference in the viability of gametes and zygotes caused by viability loci in the segregating progeny.However， the maternal cytoplasm may also be involved in the viability selection of gametes and zygotes. The objectives of thisstudy were to map the segregation distortion loci （SDL） in maize and to test the hypothesis that the viability of gametes andzygotes may also be associated with the maternal cytoplasmic environment. In the present study， a reciprocal mating designwas conducted to generate an F2-segregating population. A linkage map was constructed with 126 microsatellite markers. A whole-genome scan was performed to detect the SDL in segregating populations with different maternal cytoplasm environments.Altogether， 14 SDL with strong LOD （logarithm （base 10） of odds） supports were identified in the specifically designed F2populations. Interestingly， we found dramatic changes in the genotypic frequencies of the SDL in the two maternal cytoplasmicbackgrounds， which indicated a change in the viability of gametes and zygotes in different cytoplasmic environments. Furthermore， in the JB cytoplasmic background， most of the detected SDL and complete distortion markers exhibited similar bias patternsfavouring the Y53 alleles. These results suggested that selfish cytoplasmic elements may have an important role in shaping thepatterns of segregation distortion in F2 populations through selective viability of gametes and zygotes.

Key Words： Segregation distortion； Eytoplasm； selection； Viability； Maize

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