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

[401817 . rauscher]国际研究奖学金计划使美国科学家和工程师能够到国外进行三至二十四个月的研究。该计划的奖励为联合研究提供了机会，并利用独特或互补的设施、专业知识和国外的实验条件。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洛斯安第斯大学开展为期12个月的研究。某些密切相关的生物群体，被称为适应性辐射，具有特殊程度的形态和生态多样性。不幸的是，人们对造成这种多样性的遗传变异知之甚少。最近对植物的研究表明，与密切相关的低多样性群体中的相似基因或与其他非调节基因相比，植物调节基因（负责营养和生殖结构的发育和器官特征的基因）的进化速度在适应性辐射中有所提高。如果这种模式适用于其他植物的适应性辐射，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。本项目的目的是测试这些基因在另一种植物适应辐射中的分子进化速率。南美洲北部的埃斯帕雷提亚复合体是安第斯山脉高海拔地区适应性辐射的一个特殊例子。这些物种包括从微小的草本蔷薇到巨大的蔷薇到高大的树木，并且已经适应了多种生态条件，使它们成为进行此类研究的绝佳群体。植物调控基因，包括APETALA1， APETALA2， AGAMOUS和pisttillata的测序在几个物种的eseletia复合体，以及他们的近亲，鱼和Smallanthus。此外，一种被认为负责适应环境压力（如抗旱和抗寒）的脱氢编码基因正在被测序。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，正在测试调节和环境压力基因加速序列进化的假设，同时，正在测量遗传多样性的模式，以测试自然选择影响的证据。这项研究有助于更好地了解与植物适应性辐射有关的遗传因素。

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.