Department of Biology, Syracuse University, Syracuse, New York 13244-1270, USA.
Evolution. 2011 Sep;65(9):2699-705. doi: 10.1111/j.1558-5646.2011.01317.x. Epub 2011 May 4.
Selection to avoid inbreeding is predicted to vary across species due to differences in population structure and reproductive biology. Over the past decade, there have been numerous investigations of postcopulatory inbreeding avoidance, a phenomenon that first requires discrimination of mate (or sperm) relatedness and then requires mechanisms of male ejaculate tailoring and/or cryptic female choice to avoid kin. The number of studies that have found a negative association between male-female genetic relatedness and competitive fertilization success is roughly equal to the number of studies that have not found such a relationship. In the former case, the underlying mechanisms are largely unknown. The present study was undertaken to verify and expand upon a previous report of postcopulatory inbreeding avoidance in D. melanogaster, as well as to resolve underlying mechanisms of inbreeding avoidance using transgenic flies that express a sperm head-specific fluorescent tag. However, siblings did not have a lower fertilization success as compared to unrelated males in either the first (P(1) ) or second (P(2) ) mate role in sperm competition with a standard unrelated competitor male in our study population of D. melanogaster. Analyses of mating latency, copulation duration, egg production rate, and remating interval further revealed no evidence for inbreeding avoidance.
由于种群结构和生殖生物学的差异，避免近亲繁殖的选择预计会因物种而异。在过去的十年中，已经有许多关于交配对近亲繁殖回避的研究，这种现象首先需要区分配偶（或精子）的亲缘关系，然后需要通过雄性精液的修饰和/或隐性雌性选择来避免近亲繁殖的机制。发现雌雄遗传相关性与竞争受精成功率之间存在负相关关系的研究数量大致与未发现这种关系的研究数量相等。在前一种情况下，潜在的机制在很大程度上是未知的。本研究旨在验证和扩展之前在黑腹果蝇中发现的交配对近亲繁殖回避的报告，以及使用表达精子头特异性荧光标记的转基因果蝇来解决近亲繁殖回避的潜在机制。然而，在我们的黑腹果蝇研究群体中，与标准的无关竞争雄性相比，在精子竞争中，无论是第一（P(1)）还是第二（P(2)）个配偶角色，同系兄弟的受精成功率都不比无关雄性低。对交配潜伏期、交配持续时间、产卵率和再次交配间隔的分析进一步表明，没有证据表明存在近亲繁殖回避。
