The genus Phaseolus, native to the Americas, is composed of more than eighty wild species, five of which were domesticated in pre-Columbian times. Since the beginning of domestication events in this genus, ample opportunities for gene flow with wild relatives have existed. The present work reviews the extent of gene flow in the genus Phaseolus in primary and secondary areas of domestication with the aim of illustrating how this evolutionary force may have conditioned ecological fitness and the widespread adoption of cultigens. We focus on the biological bases of gene flow in the genus Phaseolus from a spatial and time perspective, the dynamics of wild-weedy-crop complexes in the common bean and the Lima bean, the two most important domesticated species of the genus, and the usefulness of genomic tools to detect inter and intraspecific introgression events. In this review we discuss the reproductive strategies of several Phaseolus species, the factors that may favor outcrossing rates and evidence suggesting that interspecific gene flow may increase ecological fitness of wild populations. We also show that wild-weedy-crop complexes generate genetic diversity over which farmers are able to select and expand their cultigens outside primary areas of domestication. Ultimately, we argue that more studies are needed on the reproductive biology of the genus Phaseolus since for most species breeding systems are largely unknown. We also argue that there is an urgent need to preserve wild-weedy-crop complexes and characterize the genetic diversity generated by them, in particular the genome-wide effects of introgressions and their value for breeding programs. Recent technological advances in genomics, coupled with agronomic characterizations, may make a large contribution.

中文翻译：

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菜豆的基因流及其作为生态适应度和栽培种扩展的合理驱动力

菜豆属原产于美洲，由80多种野生物种组成，其中5种是在哥伦布时代之前驯化的。自从该属的驯化事件开始以来，就存在与野生亲缘种进行基因交流的充足机会。目前的工作审查了菜豆属在驯化的主要和次要领域中基因流动的程度，目的是说明这种进化力可能如何调节生态适应性和栽培种的广泛采用。我们从时空角度着眼于菜豆属基因流的生物学基础，普通豆和利马豆这两个最重要的驯化物种-野生-杂草-作物复合体的动态，以及基因组工具检测种间和种内渗入事件的实用性。在这篇综述中，我们讨论了几种菜豆的繁殖策略，可能有利于异交率的因素以及表明种间基因流可能增加野生种群生态适应性的证据。我们还表明，野生杂草-农作物复合物产生了遗传多样性，农民可以通过该遗传多样性在驯化的主要地区之外选择和扩大其栽培品种。最终，我们认为菜豆属的生殖生物学还需要进行更多的研究，因为对于大多数物种而言，繁殖系统在很大程度上是未知的。我们还认为，迫切需要保存野生的杂草作物复合物，并表征它们产生的遗传多样性，特别是基因渗入对全基因组的影响及其对育种计划的价值。基因组学的最新技术进步以及农艺学特征可能会做出巨大贡献。