SGER: Gene Flow and Hybridization Between Introduced and Endemic Populations of Three Native Perennial Grass Species

[00:81024]种群生物学的一个基本问题是确定新基因在自然种群中的传播程度及其对进化和生态过程的影响。在植物方面，由于种子的偶然传播和恢复原生植被的努力，将新的遗传物质引入土著种群正变得越来越普遍。虽然引入新的遗传物质可能使遗传多样性很少的种群受益，但也存在严重的潜在风险。例如，当代表不同遗传群体的个体交配并杂交时，来自两个群体的遗传物质通过有性繁殖的混合可能导致杂交后代（或两代后的孙辈）难以适应当地的生态条件。这种现象被称为“杂交崩溃”，可能导致灭绝的风险增加。迄今为止，生态学家们才刚刚开始讨论这种可能性，即大规模的恢复工作可能会给后代带来这样的“毒丸”（即杂交破坏）。在这里启动的合作将是对草原物种的这种可能性的首次研究，草原物种一直是恢复工作的主要焦点。研究人员将利用分子指纹技术在加州大学管理的大面积草地/橡树林地保护区寻找三种加州本地多年生草的引进种群和常住种群之间杂交和杂交破坏的证据。

0081024Mazer and ReichmanA fundamental problem in population biology is determining the extent of the spread of novel genes in natural populations and its effect on evolutionary and ecological processes. In plants, the introduction of novel genetic material into indigenous populations is becoming more common due to the accidental spread of seeds and due to attempts to restore native vegetation. While the introduction of new genetic material may benefit populations with little genetic diversity, there are also serious potential risks. For example, when individuals representing genetically distinct populations mate and hybridize, the mixing of the genetic material from the two populations through sexual reproduction can result in hybrid offspring (or grandoffspring, two generations later) that are poorly adapted to local ecological conditions. This phenomenon is known as "hybrid breakdown" and can result in an increased risk of extinction. To date, the possibility that major restoration efforts may hold such a "poison pill" for future generations (i.e., hybrid breakdown) has just begun to be discussed by ecologists. The collaboration to be initiated here will be the first study of this possibility in grassland species, which have been a major focus of restoration efforts. The investigators will use molecular fingerprinting techniques to seek evidence for hybridization and hybrid breakdown between introduced and resident populations of three species of native California perennial grasses at an extensive grassland/oak woodland reserve managed by the University of California.