Evaluation of the genomic extent of effects of fixed inversion differences on intraspecific variation and interspecific gene flow in Drosophila pseudoobscura and D-persimilis
Evaluation of the genomic extent of effects of fixed inversion differences on intraspecific variation and interspecific gene flow in Drosophila pseudoobscura and D-persimilis
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DOI：
10.1534/genetics.106.064758
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发表时间：
2007-03-01
期刊：
影响因子：
3.3
通讯作者：
Noor, Mohamed A. F.
中科院分区：
文献类型：
--
作者：
Machado, Carlos A.;Haselkorn, Tamara S.;Noor, Mohamed A. F.
有越来越多的证据表明，染色体倒位可以促进新物种的形成或持久性，使遗传因素赋予物种特异性的适应或生殖隔离，以共同继承，并通过减少或消除渐渗。然而，倒位区域对基因渗入的影响的基因组域尚未被仔细研究。在这里，我们提出了一个详细的研究的后果，从倒位断点的距离上推断的基因流水平和分歧之间的果蝇pseudobscura和D。Persimilis。我们确定了反演断点的位置，区分D。pseudobscura和A persimilis在染色体2，XR和XL。群体遗传数据收集在特定的距离从第二条染色体的倒位断点，并在XR和XL倒位区域内的两个位点。对于倒位区以外的基因座，我们发现离最近的倒位断点的距离对D. Pseudobscura和D. Persimilis。数据符合对数关系，表明在倒位杂合子中的交叉抑制也延伸到位于倒位之外但靠近它的基因座（在1 - 2 Mb内）。此外，我们检测到一个显着减少核苷酸变异内倒第二染色体区域的D。persimilis和附近的一个断点，与这种逆转出现的情况下，并通过自然选择在这个物种中固定一致。
There is increasing evidence that chromosomal inversions may facilitate the formation or persistence of new species by allowing genetic factors conferring species-specific adaptations or reproductive isolation to be inherited together and by reducing or eliminating introgression. However, the genomic domain of influence of the inverted regions on introgression has not been carefully studied. Here, we present a detailed study on the consequences that distance from inversion breakpoints has had on the inferred level of gene flow and divergence between Drosophila pseudoobscura and D. persimilis. We identified the locations of the inversion breakpoints distinguishing D. pseudoobscura and A persimilis in chromosomes 2, XR, and XL. Population genetic data were collected at specific distances from the inversion breakpoints of the second chromosome and at two loci inside the XR and XL inverted regions. For loci outside the inverted regions, we found that distance from the nearest inversion breakpoint had a significant effect on several measures of divergence and gene flow between D. pseudoobscura and D. persimilis. The data fitted a logarithmic relationship, showing that the suppression of crossovers in inversion heterozygotes also extends to loci located outside the inversion but close to it (within 1-2 Mb). Further, we detected a significant reduction in nucleotide variation inside the inverted second chromosome region of D. persimilis and near one breakpoint, consistent with a scenario in which this inversion arose and was fixed in this species by natural selection.