A rare exception to Haldane's rule: Are X chromosomes key to hybrid incompatibilities?
A rare exception to Haldane's rule: Are X chromosomes key to hybrid incompatibilities?
复制标题
霍尔丹规则的一个罕见例外：X 染色体是杂交不相容性的关键吗？
作者：
Moran PA
哈勒定律的流行表明性染色体通常在生殖障碍和物种形成中起关键作用。然而，大多数关于Halfman规则的研究都是在具有传统性别决定系统（XY和ZW）的物种中进行的，并且对该规则的例外情况进行了充分的研究。在这里，我们测试的作用，X-连锁的不相容性在一个罕见的例外，以哈勒的规则，女性不育领域的姐妹物种（Teleogryllus oceanicus和T。commodus）。两者都有XO性别决定系统。使用三代杂交，我们将每个物种的X染色体渗入到不同的混合基因组背景中，以测试对每个杂交类型的生育力和生存力的预测。我们预测，女性与两个不同物种的X染色体将遭受生育能力和生存能力降低与女性有两个父母的X染色体。然而，我们没有发现对这种X连锁不相容性的强有力的支持。我们的研究结果排除了X-X不相容性，而是支持一个染色体间上位性的基础上杂交雌性不育。我们讨论了更广泛的影响，这些研究结果，主要是是否偏离Halfman的规则可能更普遍的物种没有二型性染色体。
The prevalence of Haldane’s rule suggests that sex chromosomes commonly have a key role in reproductive barriers and speciation. However, the majority of research on Haldane’s rule has been conducted in species with conventional sex determination systems (XY and ZW) and exceptions to the rule have been understudied. Here we test the role of X-linked incompatibilities in a rare exception to Haldane’s rule for female sterility in field cricket sister species (Teleogryllus oceanicus and T. commodus). Both have an XO sex determination system. Using three generations of crosses, we introgressed X chromosomes from each species onto different, mixed genomic backgrounds to test predictions about the fertility and viability of each cross type. We predicted that females with two different species X chromosomes would suffer reduced fertility and viability compared with females with two parental X chromosomes. However, we found no strong support for such X-linked incompatibilities. Our results preclude X–X incompatibilities and instead support an interchromosomal epistatic basis to hybrid female sterility. We discuss the broader implications of these findings, principally whether deviations from Haldane’s rule might be more prevalent in species without dimorphic sex chromosomes.