Multiple Genes Cause Postmating Prezygotic Reproductive Isolation in the Drosophila virilis Group
Multiple Genes Cause Postmating Prezygotic Reproductive Isolation in the Drosophila virilis Group
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DOI：
10.1534/g3.116.033340
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发表时间：
2016-12-01
影响因子：
2.6
通讯作者：
Ahmed-Braimah, Yasir H.
中科院分区：
文献类型：
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作者：
Ahmed-Braimah, Yasir H.
了解物种形成的遗传基础是进化生物学的一个中心问题。生殖隔离的研究为物种形成的遗传原因提供了一些见解，特别是在适合进行详细遗传检查的类群中。生殖障碍通常分为发生在受精卵形成之前（合子前）和受精卵形成之后（合子后）的障碍，后者在几十年来受到了广泛的关注。交配后但受精卵形成前发生的生殖障碍[交配前合子（PMPZ）]在基因水平上的研究尤其不足。在这里，我对两种果蝇组（D. americana 和 D. virilis）之间的 PMPZ 生殖障碍进行了表型和遗传分析。该物种对表现出强烈的 PMPZ 隔离，特别是当美洲巨蜥雄性与雌性巨蜥交配时：这些异种交配后产下的卵大约 99% 未受精。先前的研究表明，导致这种不相容性的父系基因座位于两条染色体上，其中一条（第 5 号染色体）可能携带多个因子。另一条（2 号染色体）被固定用于围绕近一半染色体的同心倒位。在这里，我展示两个结果。首先，我表明该物种杂交中的 PMPZ 很大程度上是由于异种交配中精子储存缺陷造成的。其次，使用先进的间交和回交作图方法，我确定了携带能够挽救异种受精的基因的基因组区域。我得出的结论是，美洲巨蜥雄性和雌性巨蜥之间的父系不亲和性是由 2 号和 5 号染色体上的四个或更多基因造成的。
Understanding the genetic basis of speciation is a central problem in evolutionary biology. Studies of reproductive isolation have provided several insights into the genetic causes of speciation, especially in taxa that lend themselves to detailed genetic scrutiny. Reproductive barriers have usually been divided into those that occur before zygote formation (prezygotic) and after (postzygotic), with the latter receiving a great deal of attention over several decades. Reproductive barriers that occur after mating but before zygote formation [postmating prezygotic (PMPZ)] are especially understudied at the genetic level. Here, I present a phenotypic and genetic analysis of a PMPZ reproductive barrier between two species of the Drosophila virilis group: D. americana and D. virilis. This species pair shows strong PMPZ isolation, especially when D. americana males mate with D. virilis females: approximate to 99% of eggs laid after these heterospecific copulations are not fertilized. Previous work has shown that the paternal loci contributing to this incompatibility reside on two chromosomes, one of which (chromosome 5) likely carries multiple factors. The other (chromosome 2) is fixed for a paracentric inversion that encompasses nearly half the chromosome. Here, I present two results. First, I show that PMPZ in this species cross is largely due to defective sperm storage in heterospecific copulations. Second, using advanced intercross and backcross mapping approaches, I identify genomic regions that carry genes capable of rescuing heterospecific fertilization. I conclude that paternal incompatibility between D. americana males and D. virilis females is underlain by four or more genes on chromosomes 2 and 5.