Abstract:
The evolutionary trajectories and genetic architectures underlying ecological divergence with gene flow are poorly understood. Sympatric timing types of the intertidal insect Clunio marinus (Diptera) from Roscoff (France) differ in lunar reproductive timing. One type reproduces at full moon, the other at new moon, controlled by a circalunar clock of yet unknown molecular nature. Lunar reproductive timing is a magic trait for a sympatric speciation process, as it is both ecologically relevant and entails assortative mating. Here, we show that the difference in reproductive timing is controlled by at least four quantitative trait loci (QTL) on three different chromosomes. They are partly associated with complex inversions, but differentiation of the inversion haplotypes cannot explain the different phenotypes. The most differentiated locus in the entire genome, with QTL support, is the period locus, implying that this gene could not only be involved in circadian timing but also in lunar timing. Our data indicate that magic traits can be based on an oligogenic architecture and can be maintained by selection on several unlinked loci.
摘要:
对基因流生态差异的进化轨迹和遗传结构知之甚少。来自罗斯科夫(法国)的潮间带昆虫Cluniomarinus(Diptera)的共生时间类型在月球繁殖时间上有所不同。一种类型在满月时再现,另一个在新月,由未知分子性质的圆形时钟控制。月球繁殖时机是同胞物种形成过程的神奇特征,因为它既与生态相关,又需要分类交配。这里,我们表明,繁殖时间的差异受三个不同染色体上至少四个数量性状基因座(QTL)的控制。它们部分与复杂的倒置有关,但是反转单倍型的分化不能解释不同的表型。整个基因组中分化程度最高的基因座,在QTL支持下,是周期轨迹,这意味着该基因不仅与昼夜节律有关,而且与月球时间有关。我们的数据表明,魔术性状可以基于寡基因结构,并且可以通过选择几个未连接的基因座来维持。