Almeida F C, DeSalle R
Sackler Institute for Comparative Genomics, American Museum of Natural History, New York, NY, USA.
Department of Biology, New York University, New York, NY, USA.
J Evol Biol. 2017 Mar;30(3):524-537. doi: 10.1111/jeb.13021. Epub 2016 Dec 19.
Accessory gland proteins (Acps) are part of the seminal fluid of male Drosophila flies. Some Acps have exceptionally high evolutionary rates and evolve under positive selection. Proper interactions between Acps and female reproductive molecules are essential for fertilization. These observations lead to suggestions that fast evolving Acps could be involved in speciation by promoting reproductive incompatibilities between emerging species. To test this hypothesis, we used population genetics data for three sibling species: D. mayaguana, D. parisiena and D. straubae. The latter two species are morphologically very similar and show only incipient reproductive isolation. This system allowed us to examine Acp evolution at different time frames with respect to speciation and reproductive isolation. Comparing data of 14 Acp loci with data obtained for other genomic regions, we found that some Acps show extraordinarily high levels of divergence between D. mayaguana and its two sister species D. parisiena and D. straubae. This divergence was likely driven by adaptive evolution at several loci. No fixed nucleotide differences were found between D. parisiena and D. straubae, however. Nevertheless, some Acp loci did show significant differentiation between these species associated with signs of positive selection; these loci may be involved in this early phase of the speciation process.
附属腺蛋白（Acps）是雄性果蝇精液的一部分。一些Acps具有极高的进化速率，并在正选择下进化。Acps与雌性生殖分子之间的适当相互作用对于受精至关重要。这些观察结果表明，快速进化的Acps可能通过促进新出现物种之间的生殖不相容性而参与物种形成。为了验证这一假设，我们使用了三个近缘物种的群体遗传学数据：马亚瓜纳果蝇（D. mayaguana）、巴黎果蝇（D. parisiena）和施特劳贝果蝇（D. straubae）。后两个物种在形态上非常相似，仅表现出初步的生殖隔离。这个系统使我们能够在物种形成和生殖隔离的不同时间框架内研究Acp的进化。将14个Acp基因座的数据与其他基因组区域获得的数据进行比较，我们发现一些Acps在马亚瓜纳果蝇与其两个姐妹物种巴黎果蝇和施特劳贝果蝇之间表现出极高的分化水平。这种分化可能是由几个基因座的适应性进化驱动的。然而，在巴黎果蝇和施特劳贝果蝇之间未发现固定的核苷酸差异。尽管如此，一些Acp基因座在这些物种之间确实表现出与正选择迹象相关的显著分化；这些基因座可能参与了物种形成过程的这一早期阶段。
