Lawniczak Mara K N, Begun David J
Center for Population Biology, Section of Evolution and Ecology, University of California at Davis, 95616, USA.
Genet Res. 2005 Oct;86(2):107-14. doi: 10.1017/S0016672305007755.
Sperm competition is an important fitness component in many animal groups. Drosophila melanogaster males exhibit substantial genetic variation for sperm competitive ability and females show considerable genetic variation for first versus second male sperm use. Currently, the forces responsible for maintaining genetic variation in sperm competition related phenotypes are receiving much attention. While several candidate genes contributing to the variation seen in male competitive ability are known, genes involved in female sperm use remain largely undiscovered. Without knowledge of the underlying genes, it will be difficult to distinguish between different models of sexual selection such as cryptic female choice and sexual conflict. We used quantitative trait locus (QTL) mapping to identify regions of the genome contributing to female propensity to use first or second male sperm, female refractoriness to re-mating, and early-life fertility. The most well supported markers influencing the phenotypes include 33F/34A (P2), 57B (refractoriness) and 23F/24A (fertility). Between 10% and 15% of the phenotypic variance observed in these recombinant inbred lines was explained by these individual QTLs. More detailed investigation of the regions detected in this experiment may lead to the identification of genes responsible for the QTLs identified here.
精子竞争是许多动物群体中一个重要的适合度组成部分。黑腹果蝇雄性在精子竞争能力方面表现出显著的遗传变异，而雌性在对第一只与第二只雄性精子的使用上也表现出相当大的遗传变异。目前，维持精子竞争相关表型遗传变异的因素受到了广泛关注。虽然已知有几个候选基因导致雄性竞争能力出现变异，但参与雌性精子使用的基因在很大程度上仍未被发现。如果不了解潜在基因，就很难区分不同的性选择模型，如隐性雌性选择和性冲突。我们使用数量性状基因座（QTL）定位来确定基因组中对雌性使用第一只或第二只雄性精子的倾向、雌性对再次交配的不应性以及早期生育力有贡献的区域。影响这些表型的最有力支持的标记包括33F/34A（P2）、57B（不应性）和23F/24A（生育力）。这些重组近交系中观察到的10%至15%的表型变异可由这些单个QTL解释。对本实验中检测到的区域进行更详细的研究可能会导致鉴定出负责此处所确定QTL的基因。
