Abstract：
The central abundance hypothesis predicts that local adaptation is a function of the distance to the centre of a species\' geographic range. To test this hypothesis, we gathered genomic diversity data from 49 populations, 646 individuals and 33,464 SNPs of two wild relatives of maize, the teosintes Zea mays ssp. parviglumis and Zea. mays. ssp. mexicana. We examined the association between the distance to their climatic and geographic centroids and the enrichment of SNPs bearing signals of adaptation. We identified candidate adaptive SNPs in each population by combining neutrality tests and cline analyses. By applying linear regression models, we found that the number of candidate SNPs is positively associated with niche suitability, while genetic diversity is reduced at the limits of the geographic distribution. Our results suggest that overall, populations located at the limit of the species\' niches are adapting locally. We argue that local adaptation to this limit could initiate ecological speciation processes and facilitate adaptation to global change.
摘要：
中心丰度假说预测，局部适应是到物种地理范围中心的距离的函数。为了检验这个假设，我们收集了49个群体的基因组多样性数据，两个野生玉米近缘种的646个个体和33,464个SNP，teosintesZeamaysssp。Parviglumis和Zea.梅斯.ssp.墨西哥.我们研究了与气候和地理质心的距离与具有适应信号的SNP富集之间的关联。我们通过结合中性测试和clinine分析确定了每个群体中的候选适应性SNP。通过应用线性回归模型，我们发现候选SNP的数量与利基适宜性呈正相关，而遗传多样性在地理分布的限制下减少。我们的研究结果表明，总体而言，位于物种生态位极限的种群正在当地适应。我们认为，对这一限制的本地适应可以启动生态物种形成过程并促进对全球变化的适应。
