RUI: Collaborative Research: Evolutionary Dynamics of a Color Polymorphism in the Desert Annual Linanthus parryae

现代进化生物学的目标之一是了解决定自然种群中遗传变异分布和维持的力量。两个主要的进化力量是：1)遗传漂变，基因频率的变化是由与小种群规模相关的随机过程引起的；2)自然选择，个体的差异生存和繁殖。拟议研究的目的是量化这些力量在沙漠植物Linanthus parryae种群中的相对重要性。这种植物在冬季降雨后开花，个体开白色或蓝色的花。种群遗传学领域的创始人之一休厄尔·赖特（Sewall Wright）博士此前的研究表明，该物种的种群规模相当小，这两种花色是通过随机遗传漂变在自然种群中保持下来的。另一种假设是，不同颜色的植物适应不同的当地条件，可能是由于吸引传粉者和产生种子的能力不同。因为花色是一种遗传性状，这种选择过程将导致种群基因组成的变化。拟议的研究将确定个体之间的随机事件和选择性差异如何有助于植物种群的进化变化。这些信息对我们了解生物多样性至关重要。

One of the goals of modern evolutionary biology is to understand the forces that determine the distribution and maintenance of genetic variation in natural populations. Two of the primary evolutionary forces are 1) genetic drift, the change in gene frequency due to random processes associated with small population size, and 2) natural selection, the differential survival and reproduction of individuals. The purpose of the proposed research is to quantify the relative importance of these forces in populations of the desert plant, Linanthus parryae. This species flowers after winter rains, and individuals produce either white or blue flowers. Previous research by Dr. Sewall Wright, one of the founders of the field of population genetics, suggested that the population size of this species was quite small, and that the two flower colors were maintained in natural populations by random genetic drift. The alternative hypothesis is that different colored plants are adapted to different local conditions, perhaps due to contrasting abilities to attract pollinators and produce seed. Because flower color is an inherited trait, this selective process will cause a change in the genetic make-up of the population. The proposed research will identify how random events and selective differences between individuals can contribute to evolutionary changes in plant populations. Such information is vital to our understanding of biological diversity.