Quantitative Genetic Architecture at Latitudinal Range Boundaries: Reduced Variation but Higher Trait Independence
Quantitative Genetic Architecture at Latitudinal Range Boundaries: Reduced Variation but Higher Trait Independence
复制标题
纬度范围边界的定量遗传结构：变异减少但性状独立性更高
作者：
Antoine Paccard;J. Van Buskirk;Y. Willi
物种分布限制被假设是由小种群规模和有限的遗传变异的生态相关性状，但早期的研究没有评估多变量表型的遗传变异。我们问是否在纬度边缘的分布人口改变了生态相关性状的数量遗传结构相比，中纬度人口。我们计算的进化潜力的措施在9个拟南芥种群跨越纬度范围内的物种在北美东部和中西部。纬度极端的环境减少了水的可用性，因此在潮湿和干燥处理下对植物进行了评估。我们估计遗传方差-协方差（G-）矩阵的大小，发展和水平衡相关的10个性状。在南部和北方分布边缘的人口减少了性状的遗传变异水平，但他们的G-矩阵更球形，G-矩阵的方向是无关的纬度。因此，预测的短期选择反应至少在边缘人口中心人口一样强。这些结果是一致的遗传漂变侵蚀变异和减少相关选择的有效性在分布边缘。我们的结论是，孤立性状的遗传变异预测能力差，以应对多变量选择和选择的反应可能经常大于预期的物种分布的边缘，因为遗传漂变的演变。
Species distribution limits are hypothesized to be caused by small population size and limited genetic variation in ecologically relevant traits, but earlier studies have not evaluated genetic variation in multivariate phenotypes. We asked whether populations at the latitudinal edges of the distribution have altered quantitative genetic architecture of ecologically relevant traits compared with midlatitude populations. We calculated measures of evolutionary potential in nine Arabidopsis lyrata populations spanning the latitudinal range of the species in eastern and midwestern North America. Environments at the latitudinal extremes have reduced water availability, and therefore plants were assessed under wet and dry treatments. We estimated genetic variance-covariance (G-) matrices for 10 traits related to size, development, and water balance. Populations at southern and northern distribution edges had reduced levels of genetic variation across traits, but their G-matrices were more spherical; G-matrix orientation was unrelated to latitude. As a consequence, the predicted short-term response to selection was at least as strong in edge populations as in central populations. These results are consistent with genetic drift eroding variation and reducing the effectiveness of correlational selection at distribution margins. We conclude that genetic variation of isolated traits poorly predicts the capacity to evolve in response to multivariate selection and that the response to selection may frequently be greater than expected at species distribution margins because of genetic drift.
影响因子：
3.3
作者：
D. Houle
通讯作者：
D. Houle