Genetics of reproductive isolation in the Drosophila simulans clade: DNA marker-assisted mapping and characterization of a hybrid-male sterility gene, Odysseus (Ods).
Genetics of reproductive isolation in the Drosophila simulans clade: DNA marker-assisted mapping and characterization of a hybrid-male sterility gene, Odysseus (Ods).
复制标题
模拟果蝇进化枝中生殖隔离的遗传学：杂交雄性不育基因 Odysseus (Ods) 的 DNA 标记辅助作图和表征。
DOI：
10.1093/genetics/134.1.261
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发表时间：
1993
期刊：
影响因子：
3.3
通讯作者：
Wu,ML
中科院分区：
文献类型：
--
作者：
Perez,DE;Wu,CI;Johnson,NA;Wu,ML
在这项研究中，我们解决了果蝇种间杂种中是否存在导致完全雄性不育的主要基因的问题，如果存在，如何在分子水平上表征这些基因。我们的方法是通过重复回交 20 代以上，将毛里求斯果蝇（或 Sechellia 果蝇）的 X 染色体小片段渗入到模拟果蝇中。基因渗入通过可见突变和一系列 DNA 标记进行监测。我们比较了导致雄性不育的基因渗入程度与不导致雄性不育的基因渗入程度。如果存在主要的不育因素，则这两类基因渗入之间应该存在明显的界限，并且它们的断点应该划分这样的基因。此外，如果雄性不育是与基因渗入相关的唯一主要适应性效应，则重组分析应该产生由经典三点杂交预测的模式。遗传和分子分析都表明，在 16D 的细胞学间隔中，存在来自 D. mauritiana 的主要不育因子，我们将其命名为 Odysseus (Ods)。因此，我们正式确定了推断基因渗入中主基因存在的三个标准：（1）不育的完全外显率，（2）重组分析中的互补性，以及（3）物理分界。来自 D. sechellia 的 Ods 渗入不会导致不育。我们收集的 22 个基因渗入在这个大约 500 kb 的区间内有断点，使得可以更精确地描绘 Ods 以进行分子鉴定。重组分析还揭示了渐渗片段的复杂性——即使是相对较短的片段也可能含有第二个雄性不育因子和部分活力基因，并且也可能干扰交叉。与 Ods 和/或第二个因素相关的生精缺陷通过相差显微镜进行表征。
In this study, we address the question of whether there exist major genes that cause complete male sterility in the interspecific hybrids of Drosophila and, if they do, how these genes may be characterized at the molecular level. Our approach is to introgress small segments of the X chromosome from Drosophila mauritiana (or Drosophila sechellia) into Drosophila simulans by repeated backcrosses for more than 20 generations. The introgressions are monitored by both visible mutations and a series of DNA markers. We compare the extent of introgressions that cause male sterility with those that do not. If a major sterility factor exists, there should be a sharp boundary between these two classes of introgressions and their breakpoints should demarcate such a gene. Furthermore, if male sterility is the only major fitness effect associated with the introgression, recombination analysis should yield a pattern predicted by the classical three-point cross. Both the genetic and molecular analyses suggest the presence of a major sterility factor from D. mauritiana, which we named Odysseus (Ods), in the cytological interval of 16D. We thus formalize three criteria for inferring the existence of a major gene within an introgression: (1) complete penetrance of sterility, (2) complementarity in recombination analysis, and (3) physical demarcation. Introgressions of Ods from D. sechellia do not cause sterility. Twenty-two introgressions in our collection have breakpoints in this interval of about 500 kb, making it possible to delineate Ods more precisely for molecular identification. The recombination analysis also reveals the complexity of the introgressed segments--even relatively short ones may contain a second male sterility factor and partial viability genes and may also interfere with crossovers. The spermatogenic defects associated with Ods and/or a second factor were characterized by phase-contrast microscopy.