Department of Integrative Biology, Oregon State University, Corvallis, OR, 97331, USA.
Sci Rep. 2021 Oct 1;11(1):19551. doi: 10.1038/s41598-021-99026-0.
"Synthetic recombinant" populations have emerged as a useful tool for dissecting the genetics of complex traits. They can be used to derive inbred lines for fine QTL mapping, or the populations themselves can be sampled for experimental evolution. In the latter application, investigators generally value maximizing genetic variation in constructed populations. This is because in evolution experiments initiated from such populations, adaptation is primarily fueled by standing genetic variation. Despite this reality, little has been done to systematically evaluate how different methods of constructing synthetic populations shape initial patterns of variation. Here we seek to address this issue by comparing outcomes in synthetic recombinant Saccharomyces cerevisiae populations created using one of two strategies: pairwise crossing of isogenic strains or simple mixing of strains in equal proportion. We also explore the impact of the varying the number of parental strains. We find that more genetic variation is initially present and maintained when population construction includes a round of pairwise crossing. As perhaps expected, we also observe that increasing the number of parental strains typically increases genetic diversity. In summary, we suggest that when constructing populations for use in evolution experiments, simply mixing founder strains in equal proportion may limit the adaptive potential.
“合成重组”群体已成为剖析复杂性状遗传的有用工具。它们可用于衍生近交系进行精细 QTL 作图，或者可以对群体本身进行采样进行实验进化。在后一种应用中，研究人员通常重视在构建的群体中最大化遗传变异。这是因为从这样的群体中启动的进化实验中，适应主要由现成的遗传变异提供燃料。尽管如此，人们很少系统地评估构建合成群体的不同方法如何塑造初始变异模式。在这里，我们通过比较使用两种策略之一创建的合成重组酿酒酵母群体的结果来解决这个问题：同源菌株的成对杂交或按相等比例简单混合。我们还探讨了改变亲本菌株数量的影响。我们发现，当群体构建包括一轮成对杂交时，最初存在更多的遗传变异并得到维持。也许可以预料到的是，我们还观察到增加亲本菌株的数量通常会增加遗传多样性。总之，我们建议在构建用于进化实验的群体时，简单地按相等比例混合起始菌株可能会限制适应潜力。
