Variation in recombination rate across the X chromosome of Anopheles gambiae
Variation in recombination rate across the X chromosome of Anopheles gambiae
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DOI：
10.4269/ajtmh.2006.75.901
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发表时间：
2006-11-01
影响因子：
3.3
通讯作者：
Besansky, Nora J.
中科院分区：
文献类型：
--
作者：
Pombi, Marco;Stump, Aram D.;Besansky, Nora J.
冈比亚按蚊的M和S分子形式被认为是早期物种，尽管残留的基因交换。在分子形式（“物种形成岛”）之间强烈区分的三个小基因组区域中，两个位于着丝粒附近，在2号染色体和X染色体的左臂上。为了验证这些岛屿中重组减少的预测，我们使用两个m型菌株估计了X染色体上微卫星位点之间的重组率。在大多数染色体上，重组发生在每百万碱基1厘米（cM Mb(-1)），这个值与冈比亚芽孢杆菌和其他真核生物的全基因组平均值非常接近。重组在端粒端高得多，bbb7 cM Mb（-1）。在着丝点末端的物种形成岛中，重组急剧减少至接近0.2 cM Mb(-1)，这与减少重组在基因流动中维持新生物种分化的作用一致。
The M and S molecular forms of Anopheles gambiae are considered to be incipient species, despite residual gene exchange. Of the three small genome regions that are strongly differentiated between the molecular forms ("speciation islands"), two are located near centromeres, on the left arm of chromosome 2 and the X chromosome. To test the prediction of reduced recombination in these islands, we estimated recombination rates between microsatellite loci on the X chromosome using two M-form strains. Across most of the chromosome, recombination occurred at similar to 1 centimorgan per megabase (cM Mb(-1)), a value closely matching the genome-wide average estimated for A. gambiae and for other eukaryotes. Recombination was much higher at the telomeric end, > 7 cM Mb(-1). In the speciation island at the centromeric end, recombination was sharply reduced to similar to 0.2 cM Mb(-1), consistent with a role for reduced recombination in maintaining differentiation between nascent species despite gene flow.