The maternal cytoplasmic environment may be involved in the viability selection of gametes and zygotes
The maternal cytoplasmic environment may be involved in the viability selection of gametes and zygotes
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DOI：
10.1038/hdy.2012.89
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发表时间：
2012-11
期刊：
影响因子：
3.8
通讯作者：
Z. Tang;X. Wang;M. Zhang;Y. H. Zhang;D. Deng;C. Xu
中科院分区：
文献类型：
--
作者：
Z. Tang;X. Wang;M. Zhang;Y. H. Zhang;D. Deng;C. Xu
分离扭曲是一种现象，即观察到的基因型频率超出了预期的孟德尔分离比，它越来越被认为是一种潜在的强大进化力量。分离畸变的主要原因是由分离后代的生存位点引起的配子和受子的生存能力差异。然而，母细胞质也可能参与配子和合子的生存力选择。本研究的目的是绘制玉米的分离扭曲位点（SDL），并验证配子和受精卵的生存能力也可能与母体细胞质环境有关的假设。在本研究中，进行了反向交配设计，以产生f2隔离群体。用126个微卫星标记构建连锁图谱。采用全基因组扫描检测不同母细胞质环境分离群体中的SDL。在专门设计的F2群体中，共鉴定出14个具有较强LOD（以10为基数的对数）支持的SDL。有趣的是，我们发现在两种母细胞质背景下SDL的基因型频率发生了巨大变化，这表明配子和受精卵在不同细胞质环境下的生存能力发生了变化。此外，在JB细胞质背景下，大多数检测到的SDL和完全畸变标记都表现出类似的偏向Y53等位基因的模式。这些结果表明，自私的细胞质元件可能通过配子和合子的选择活力在F2群体中形成分离扭曲模式中起重要作用。
Segregation distortion is the phenomenon whereby the observed genotypic frequencies of a locus fall outside the expected Mendelian segregation ratio, and it is increasingly recognised as a potentially powerful evolutionary force. The main reason for segregation 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 this study were to map the segregation distortion loci (SDL) in maize and to test the hypothesis that the viability of gametes and zygotes may also be associated with the maternal cytoplasmic environment. In the present study, a reciprocal mating design was 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 F2 populations. Interestingly, we found dramatic changes in the genotypic frequencies of the SDL in the two maternal cytoplasmic backgrounds, 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 patterns favouring the Y53 alleles. These results suggested that selfish cytoplasmic elements may have an important role in shaping the patterns of segregation distortion in F2 populations through selective viability of gametes and zygotes.