Evolution of sexual dimorphism

在所有具有不同性别的动物和植物物种中，雄性和雌性的形态不同，有时行为也不同。我们知道，之所以出现这些差异，是因为两性在繁殖中扮演不同的角色，因此受到不同的选择压力。我们还不明白的是，雄性和雌性之间的选择差异究竟是如何导致两性之间的表型差异的。本项目探讨这一问题。它建议调查不同的选择压力如何导致等位基因的积累，这是有益的一种性别，但有害的其他，在种群的果蝇果蝇，以及这种积累是如何相关的程度上选择不同的性别。此外，它的目的是研究二型性的进化，通过创造一个新的二型性，通过分歧人工选择目前单形字符在D。黑腹菌这种方法将使人们了解种群对雄性和雌性的不同选择的反应速度和程度，以及这种反应在基因组中的位置（性染色体X与常染色体）。此外，该实验将揭示性别之间的表型差异是如何在男性和女性的基因表达水平上进行调节的，以及哪些因素影响这种调节对选择做出反应的能力。总之，这些方法有可能阐明导致自然界中普遍存在的现象的进化步骤，并深入了解其背后的分子过程。

In all animal and plant species with separate sexes, males and females differ in their morphology and sometimes behaviour. We know that these differences have arisen because the sexes have different roles in reproduction and are therefore under different selection pressures. What we have not understood yet is how exactly the difference in selection between males and females leads the phenotypic divergence between the two sexes. The present project addresses this question. It proposes to investigate how divergent selection pressures lead to the accumulation of alleles that are beneficial to one sex but detrimental to the other, in populations of the fruitfly Drosophila melanogaster, and how this accumulation is related to the extent to which selection differs between the sexes. Further, it aims at studying the evolution of dimorphism by creating a novel dimorphism through divergent artificial selection on a presently monomorphic character in D. melanogaster. This approach will give insight in the rate and degree to which populations can respond to divergent selection on males and females and where this response is located in the genome (on the sex-chromosome X vs. the autosomes). Further, the experiment will reveal how the phenotypic divergence between the sexes is regulated at the level of the expression of genes in males and females and what factors affect the ability of this regulation to respond to selection. Taken together, these approaches have the potential to elucidate the evolutionary steps leading to a phenomenon that is ubiquitous in nature and give insights in the molecular processes that underlie it.