Galvin Jake, Yedigarian Sevan, Rahman Mohammad, Borziak Kirill, DeNieu Michael, Larson Erica L, Manier Mollie K
Department of Biological Sciences, George Washington University, Washington, United States.
Department of Biology, Syracuse University, Syracuse, United States.
J Evol Biol. 2025 Sep 6;38(8):1100-1112. doi: 10.1093/jeb/voaf065.
Spermatozoal morphology varies widely within and among species, often corresponding to the shape of the female sperm storage organs in ways that can impact fertilization. To understand genetic mechanisms of sperm length variation, we compared gene expression patterns in the testes of Drosophila melanogaster males that produce either long or short sperm. We found that genes upregulated in long sperm testes are enriched for long noncoding RNAs and seminal fluid proteins (Sfps). Transferred to the female during mating, Sfps are secreted by the male accessory glands and affect female remating rate, physiology, and behavior. While sperm and Sfps are both critical for male reproductive success, they are largely considered to be functionally and genetically independent, and Sfps have no known function in testes. Knockouts of two Sfps upregulated in long sperm males, Sex Peptide and ovulin, resulted in shorter sperm, suggesting Sfps may contribute to sperm length development. Consistent with this, knockout of accessory gland function did not affect sperm length, indicating accessory gland expression had no influence on spermatogenesis. We also found that long sperm males were better able to delay female remating, suggesting a dual advantage in sperm competition by both delaying female remating and resisting sperm displacement. However, we found that the delay in female remating does not necessarily increase progeny or paternity success. Thus, multiple components of the ejaculate promote male reproductive success at different stages of reproduction, but the realized fitness advantages in sperm competition are uncertain.
精子形态在物种内部和物种之间差异很大，通常与雌性精子储存器官的形状相对应，这种对应方式可能会影响受精。为了了解精子长度变异的遗传机制，我们比较了产生长精子或短精子的黑腹果蝇雄性个体睾丸中的基因表达模式。我们发现，在长精子睾丸中上调的基因富含长链非编码RNA和精液蛋白（Sfps）。精液蛋白在交配过程中转移到雌性体内，由雄性附腺分泌，影响雌性的再次交配率、生理和行为。虽然精子和精液蛋白对雄性生殖成功都至关重要，但它们在很大程度上被认为在功能和遗传上是独立的，并且精液蛋白在睾丸中没有已知功能。在长精子雄性个体中上调的两种精液蛋白——性肽和卵白蛋白的基因敲除导致精子变短，这表明精液蛋白可能有助于精子长度的发育。与此一致的是，附腺功能的基因敲除并不影响精子长度，这表明附腺表达对精子发生没有影响。我们还发现，长精子雄性个体更能延迟雌性的再次交配，这表明在精子竞争中通过延迟雌性再次交配和抵抗精子置换具有双重优势。然而，我们发现雌性再次交配的延迟不一定会增加后代数量或父权成功率。因此，射精的多个组成部分在生殖的不同阶段促进雄性生殖成功，但在精子竞争中实际实现的适应性优势尚不确定。
