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

当一个生物种群内的迁移很少时，个体的出生地与其父母的出生地之间的距离并不比邻居之间的距离大多少。在这些条件下，不同类型的基因可能在局部比平均水平更常见或更少，这纯粹是随机的。这些随机遗传变化与自然选择导致的适应性进化的非随机遗传变化非常不同。然而，种群中局部区域基因组成的随机变化可能对种群在自然选择指导下的特定进化途径产生重大影响。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原产于北美高草草原的植物种群的随机遗传变化。将测量每个研究人群中不同区域由于随机变化而具有不同基因组成的程度。还将测量花粉粒和种子的迁移距离，以确定随机遗传变化的数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之间分布的信息也将有助于在曾经广阔的高草大草原仅存的几个区域内建立保护遗传多样性的管理准则。

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.