Cline coupling and uncoupling in a stickleback hybrid zone
Cline coupling and uncoupling in a stickleback hybrid zone
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刺鱼杂交区的斜线耦合和解耦合
DOI：
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发表时间：
2015
期刊：
影响因子：
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通讯作者：
D. Schluter
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文献类型：
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作者：
T. Vines;Anne C. Dalziel;Arianne Y. Albert;Thor Veen;P. Schulte;D. Schluter
一个遗传位点上强烈的生态选择可以在不同环境下保持种群间等位基因频率的差异，即使是在杂交的情况下。当分散位点上的等位基因发生紧密连锁不平衡时，选择作为一个整体作用于它们，可以显著减少基因流动。对于跨杂交区杂交的种群，位点之间的连锁不平衡会迫使亲系共享相同的斜率和中心。然而，强大的生态选择可以使品种远离其他品种，减少连锁不平衡，削弱基因流动的障碍。我们在河栖棘鱼和无源棘鱼之间的杂交区寻找这种“突变解耦”效应，在两个已知的在不同自然选择下的基因（Eda和ATP1a1）和五个在淡水棘鱼中反复进化的形态特征上。我们使用了10个匿名snp来描述区域的形状。我们发现Eda、ATP1a1和4个形态性状的曲线是一致和一致的，这表明对每个性状的直接选择被连锁不平衡产生的间接选择所抵消。有趣的是，胸鳍长度的变化更陡峭，在200米的下游发生位移，两个匿名snp也有陡峭的变化。
Strong ecological selection on a genetic locus can maintain allele frequency differences between populations in different environments, even in the face of hybridization. When alleles at divergent loci come into tight linkage disequilibria, selection acts on them as a unit and can significantly reduce gene flow. For populations interbreeding across a hybrid zone, linkage disequilibria between loci can force clines to share the same slopes and centers. However, strong ecological selection can push clines away from the others, reducing linkage disequilibria and weakening the barrier to gene flow. We looked for this ‘cline uncoupling’ effect in a hybrid zone between stream resident and anadromous sticklebacks at two genes known to be under divergent natural selection (Eda and ATP1a1) and five morphological traits that repeatedly evolve in freshwater stickleback. We used 10 anonymous SNPs to characterize the shape of the zone. We found that the clines at Eda, ATP1a1, and four morphological traits were concordant and coincident, suggesting that direct selection on each is outweighed by the indirect selection generated by linkage disequilibria. Interestingly, the cline for pectoral fin length was much steeper and displaced 200m downstream, and two anonymous SNPs also had steep clines.