Nelson Joel T, Motamayor Juan C, Cornejo Omar E
School of Biological Sciences, Washington State University, Pullman, WA, USA.
Universal Genetic Solutions, LLC, Orlando, FL, USA.
Mol Ecol. 2021 Feb;30(3):656-669. doi: 10.1111/mec.15754. Epub 2020 Dec 26.
Predicting the potential fate of a species in the face of climate change requires knowing the distribution of molecular adaptations across the geographic range of the species. In this work, we analysed 79 genomes of Theobroma cacao, an Amazonian tree known for the fruit from which chocolate is produced, to evaluate how local and regional molecular signatures of adaptation are distributed across the natural range of the species. We implemented novel techniques that incorporate summary statistics from multiple selection scans to infer selective sweeps. The majority of the molecular adaptations in the genome are not shared among populations. We show that ~71.5% of genes under selection also show significant associations with changes in environmental variables. Our results support the interpretation that these genes contribute to local adaptation of the populations in response to abiotic factors. We also found strong patterns of molecular adaptation in a diverse array of disease resistance genes (6.5% of selective sweeps), suggesting that differential adaptation to pathogens also contributes significantly to local adaptations. Our results are consistent with the interpretation that local selective pressures are more important than regional selective pressures in explaining adaptation across the range of a species.
预测一个物种在气候变化面前的潜在命运，需要了解分子适应性在该物种地理分布范围内的情况。在这项研究中，我们分析了79个可可树基因组，这是一种亚马逊树木，以其果实可生产巧克力而闻名，目的是评估适应性的局部和区域分子特征如何在该物种的自然分布范围内分布。我们采用了新技术，这些技术结合了来自多个选择扫描的汇总统计数据来推断选择性清除。基因组中的大多数分子适应性在不同种群之间并不共享。我们发现，约71.5%的受选择基因也与环境变量的变化存在显著关联。我们的结果支持这样的解释，即这些基因有助于种群对非生物因素的局部适应。我们还在各种各样的抗病基因中发现了强烈的分子适应模式（占选择性清除的6.5%），这表明对病原体的差异适应也对局部适应有显著贡献。我们的结果与这样的解释一致，即在解释一个物种分布范围内的适应性时，局部选择压力比区域选择压力更重要。
