Eizadshenass Sogol, Singh Rama S
Department of Biology, McMaster University, 1280 Main Street West, Hamilton, ON L8S 4K1, Canada.
Genome. 2015 Sep;58(9):405-13. doi: 10.1139/gen-2015-0053. Epub 2015 Aug 19.
Haldane's rule has been the basis of speciation research during the last 30 years. Most studies have focused on the nature of incompatibilities in the hybrid male, but not much attention has been given to the genetic basis of fertility and inviability in hybrid females. Hybridizations between Drosophila simulans and Drosophila mauritiana produce fertile females and sterile males. Here, we re-examined the level of fertility in reciprocal F1 females of these two species and looked for the presence of maternal effects. Our results show that the reciprocal F1 females of D. simulans and D. mauritiana hybridizations are fully fertile and in fact show a significant level of heterosis in the rate of oviposition but display reduced egg hatching in one direction. Reduced egg hatching was observed in the progenies of F1 hybrid females with D. mauritiana as mother, the same cross that showed a stronger negative effect on F1 male fertility. A review of the literature on the hybridizations in Lepidoptera also showed a maternal effect on inviability when reciprocal crosses produced asymmetric results. Our findings point to the importance of maternal effects in the evolution of embryo inviability and thus enhancing the process of speciation through the evolution of hybrid inviability.
在过去30年里，霍尔丹法则一直是物种形成研究的基础。大多数研究都集中在杂交雄性的不相容性本质上，但对杂交雌性的生育力和生存力的遗传基础关注不多。拟暗果蝇和毛里求斯果蝇之间的杂交产生可育雌性和不育雄性。在这里，我们重新审视了这两个物种正反交F1雌性的生育力水平，并寻找母体效应的存在。我们的结果表明，拟暗果蝇和毛里求斯果蝇杂交的正反交F1雌性完全可育，事实上在产卵率上显示出显著的杂种优势水平，但在一个方向上卵孵化率降低。在以毛里求斯果蝇为母本的F1杂交雌性后代中观察到卵孵化率降低，同一杂交组合对F1雄性生育力也有更强的负面影响。对鳞翅目杂交文献的回顾也表明，当正反交产生不对称结果时，母体效应会影响生存力。我们的研究结果指出了母体效应在胚胎生存力进化中的重要性，从而通过杂交不存活的进化增强物种形成过程。
