Mank Judith E
Edward Grey Institute, Department of Zoology, University of Oxford, Oxford, UK.
Genet Res (Camb). 2009 Oct;91(5):355-63. doi: 10.1017/S0016672309990255.
Early karyotypic work revealed that female and male recombination rates in many species show pronounced differences, and this pattern of heterochiasmy has also been observed in modern linkage mapping studies. Several hypotheses to explain this phenomenon have been offered, ranging from strictly biological mechanisms related to the gametic differences between the sexes, to more evolutionary models based on sexually antagonistic selection. However, despite the long history of interest in heterochiasmy, empirical data has failed to support any theory or pattern consistently. Here I test two alternative evolutionary hypotheses regarding heterochiasmy across the eutherian mammals, and show that sexual dimorphism, but not sperm competition, is strongly correlated with recombination rate, suggesting that sexual antagonism is an important influence. However, the observed relationship between heterochiasmy and sexual dimorphism runs counter to theoretical predictions, with male recombination higher in species with high levels of sexual dimorphism. This may be the response to male-biased dispersal, which, rather than the static male fitness landscape envisioned in the models tested here, could radically shift optimal male fitness parameters among generations.
早期的核型研究表明，许多物种中雌性和雄性的重组率存在显著差异，这种异交叉现象在现代连锁图谱研究中也有观察到。人们提出了几种假说来解释这一现象，从与两性配子差异相关的严格生物学机制，到基于性对抗选择的更多进化模型。然而，尽管对异交叉现象的研究历史悠久，但实证数据一直未能始终如一地支持任何理论或模式。在这里，我测试了关于真兽亚纲哺乳动物异交叉现象的两种替代性进化假说，结果表明，性二态性而非精子竞争与重组率密切相关，这表明性对抗是一个重要影响因素。然而，观察到的异交叉现象与性二态性之间的关系与理论预测相悖，在性二态性程度高的物种中雄性重组率更高。这可能是对雄性偏向扩散的一种反应，这种扩散可能会在代际之间从根本上改变最优雄性适应度参数，而不是像这里测试的模型中设想的静态雄性适应度格局。
