RUI: Isolation by Distance and Spatial Genetic Structure in Plant Populations

当生物种群内几乎没有迁徙时，个体出生地和父母出生地之间的距离不会比邻居之间的距离大很多。在这些条件下，不同类型的基因可能会在局部变得比平均水平更常见或更不常见，这完全是随机的。这些随机的遗传变化与自然选择带来的导致适应性进化的非随机遗传变化有很大的不同。然而，种群内局部区域基因组成的随机变化可能会对自然选择引导种群的特定进化路径产生重大影响。因此，为了理解自然选择可能带来的进化变化的类型，必须确定随机变化的重要性。研究人员将研究两种植物自然种群内的随机遗传变化，这两种植物原产于北美的高草草原。将测量每个研究种群内不同地区由于随机变化而具有不同遗传组成的程度。还将测量花粉粒和种子的迁移距离，以查看随机遗传变化量是否与目前的迁移模式一致。关于遗传变异如何在不同地区分布的信息也将有助于在曾经广阔的高草草原的少数剩余区域内制定保护遗传多样性的管理指导方针。

When there is very little migration within a population of living organisms, the distance between the birthplaces of individuals and the birthplaces of their parents is not much greater than the distance between neighbors. Under these conditions different types of genes may become locally more or less common than average by purely random chance. These random genetic changes are very different from the nonrandom genetic changes brought about by natural selection that lead to adaptive evolution. However, random changes in the genetic composition of local areas within a population can have a great impact on the specific evolutionary pathway along which a population is guided by natural selection. Therefore, to understand the types of evolutionary changes that may be brought about by natural selection, the importance of random changes must be determined. The investigators will study random genetic changes within natural populations of two plant species that are native to the tallgrass prairies of North America. The extent to which different local areas within each study population have different genetic compositions as a result of random changes will be measured. Migration distances of pollen grains and seeds will also be measured to see if the amount of random genetic change is consistent with present migration patterns. The information on how genetic variation is distributed among different local areas will also be useful in establishing management guidelines for the conservation of genetic diversity within the few remaining tracts of the once vast tallgrass prairie.