Ecological Genetics of Sex-Chromosome Traits in the Tiger Swallowtail Butterfly Hybrid Zone

[9981608]波特虎燕尾蝶和加拿大凤蝶在美国东部一个狭窄的杂交区相遇。它们在生态学上具有重要的差异，包括控制冬季滞育和模仿一种相关的、令人讨厌的物种（仅限雌性）。这些特征是由X染色体和y染色体上的基因控制的。杂交区生物学的理论进步，比如这一个，已经允许测量自然选择作用于生态上重要特征的强度，以及其他基因转移到相反物种的速率。作者将利用这一理论来衡量自然选择在滞育、翅膀着色和其他X和y相关特征上的作用强度。他们将做平行场实验来衡量对这些特征的选择。最后，他们将测量这种选择阻止其他基因在这些杂交物种之间传播的能力。性染色体在生物学中起着核心作用，并且具有与其他染色体不同的一些特性，但是生物学家很少从自然界获得关于进化力量如何影响性染色体变异的数据。这项研究的作者利用这些蝴蝶生物学的关键特征来研究作用于性染色体的进化压力和相关物种之间的基因传播。

9981608 PorterThe tiger swallowtail butterfly species Papilio glaucus and P. canadensismeet in a narrow zone of hybridization across the eastern US. They differin ecologically important traits, including the control of winter diapauseand the mimicry (only by P. glaucus females) of a related, distastefulspecies. These traits are controlled by genes on the X- and Y-chromosomes.Theoretical advances in the biology of hybrid zones, such as this one,have allowed the measurement of the strength of natural selection acting onecologically important traits, as well as the rate that other genes canslip through to the opposite species. The authors will use this theory tomeasure the strength of natural selection acting on diapause, wingcoloration and other X- and Y-associated traits. They will do parallelfield experiments to measure selection on these traits. Finally, they willmeasure the ability of this selection to block the spread of other genesbetween these hybridizing species.Sex chromosomes play a central role in biology and have several propertiesunique from other chromosomes, but biologists have few data from natureabout how evolutionary forces affect sex-chromosome variation. The authorsof this study exploit key features of the biology of these butterflies tostudy the evolutionary pressures acting on sex chromosomes and the spreadof genes between related species.