Data from: Cis- and trans-acting genetic factors contribute to heterogeneity in the rate of crossing over between the Drosophila simulans clade species

In the genus Drosophila, variation in recombination rates has been found within and between species. Genetic variation for both cis- and trans-acting factors has been shown to affect recombination rates within species, but little is known about the genetic factors that affect differences between species. Here we estimate rates of crossing over for seven segments that tile across the euchromatic length of the X chromosome in the genetic backgrounds of three closely related Drosophila species. We first generated a set of Drosophila mauritiana lines each having two semi-dominant visible markers on the X chromosome and then introgressed these doubly marked segments into the genetic backgrounds of its sibling species, D. simulans and D. sechellia. Using these 21 lines (7 segments, 3 genetic backgrounds) we tested whether recombination rates within the doubly marked intervals differed depending on genetic background. We find significant heterogeneity among intervals and among species backgrounds. Our results suggest that a combination of both cis- and trans-acting factors have evolved among the three D. simulans clade species and interact to affect recombination rate.

在果蝇属（Drosophila）中，种内与种间均存在重组率的变异。已有研究证实，顺式作用（cis-acting）与反式作用（trans-acting）因子的遗传变异均可影响物种内的重组率，但对于介导物种间重组率差异的遗传机制，目前仍所知甚少。本研究针对覆盖X染色体常染色质全域的7个染色体区段，在3个近缘果蝇物种的遗传背景下估算了交换（crossing over）率。我们首先构建了一批毛里求斯果蝇（Drosophila mauritiana）品系，每个品系的X染色体上均携带两个半显性可见标记；随后将这些携带双标记的染色体区段渐渗至其姊妹种——拟果蝇（D. simulans）与塞氏果蝇（D. sechellia）的遗传背景中。利用这21个品系（7个区段×3种遗传背景），我们检验了双标记区间内的重组率是否因遗传背景不同而存在差异。研究发现，不同染色体区段以及不同物种遗传背景下的重组率均存在显著异质性。本研究结果表明，在拟果蝇支系（D. simulans clade）的3个物种中，顺式作用与反式作用因子均发生了演化，且二者相互作用共同调控重组率。