International Research Fellowship Program: The Molecular Evolution of Floral Regulatory and Environmental Stress-Induced Genes in an Andean Adaptive Radiation

国际研究奖学金计划使美国科学家和工程师能够在国外进行三到二十四个月的研究。该计划的奖项提供了联合研究的机会，并利用国外独特或互补的设施，专业知识和实验条件。该奖项将支持Jason Rauscher博士与圣地亚哥Madrinan博士在哥伦比亚波哥大的Universidad de Los安第斯山脉进行为期12个月的研究。某些密切相关的生物群体，称为适应辐射，其特点是形态和生态多样性的特殊程度。不幸的是，很少有人知道这种多样性的遗传变异。最近对植物的研究表明，与密切相关的低多样性群体中的类似基因或与其他非调控基因相比，花调控基因（负责营养和生殖结构的发育和器官特性的基因）的进化速率在适应性辐射中升高。如果这种模式也适用于其他植物的适应辐射，它可能有助于我们开始更好地了解生物多样性的遗传起源。该项目的目的是测试另一种植物适应性辐射中这些基因的分子进化速率。南美洲北方的埃斯佩莱蒂亚复合体是来自高安第斯山脉的适应性辐射的一个特殊例子。这些物种包括从小型草本植物到巨型植物到高大树木的一切，并且已经适应了各种生态条件，使它们成为此类研究的优秀群体。花的调控基因，包括APETALA1，APETALA2，AGAMOUS和PISTILLATA正在测序的几个物种在Espeletia复杂，以及在他们最近的亲戚，鱼介和Smallanthus。此外，一个被认为负责适应干旱和抗寒等环境压力的编码基因正在测序中。通过比较物种之间的进化速度和改变蛋白质的基因突变的数量，正在检验调节基因和环境压力基因序列加速进化的假设，同时正在测量遗传多样性的模式，以检验自然选择效应的证据。这项研究有助于更好地理解植物适应辐射的遗传因素。

0401817RauscherThe International Research Fellowship Program enables U.S. scientists and engineers to conduct three to twenty-four months of research abroad. The program's awards provide opportunities for joint research, and the use of unique or complementary facilities, expertise and experimental conditions abroad.This award will support a twelve-month research fellowship by Dr. Jason Rauscher to work with Dr. Santiago Madrinan at the Universidad de Los Andes in Bogota, Colombia.Certain groups of closely related organisms, known as adaptive radiations, are characterized by an exceptional degree of morphological and ecological diversity. Unfortunately, little is understood as to the genetic variation that is responsible for this diversity. Recent studies in plants have suggested that rates of evolution in floral-regulatory genes (those responsible for the development and organ identity of vegetative and reproductive structures) are elevated in adaptive radiations when compared to similar genes in closely related, low-diversity groups or compared to other non-regulatory genes. If this pattern holds true in other plant adaptive radiations, it may help us begin to understand better the genetic origins of biological diversity. The aim of this project is to test rates of molecular evolution in these genes in another plant adaptive radiation. The Espeletia complex of northern South America is an exceptional example of adaptive radiation from the high Andes Mountains. These species include everything from tiny herbaceous rosettes to giant rosettes to tall trees, and have adapted to a diversity of ecological conditions, making them an excellent group for such a study. Floral regulatory genes, including APETALA1, APETALA2, AGAMOUS and PISTILLATA are being sequenced for several species in the Espeletia complex, as well as in their closest relatives, Ichthyothere and Smallanthus. In addition, a dehydrin-encoding gene thought to be responsible for adaptation to environmental stresses such as drought and cold resistance is being sequenced. By comparing rates of evolution and the number of protein-altering genetic mutations between species, the hypothesis of accelerated sequence evolution in regulatory and environmental stress genes is being tested, while at the same time, patterns of genetic diversity are being measured to test for evidence of the effect of natural selection. This research is helping to realize a better understanding of the genetic factors involved in plant adaptive radiations.