REU: Molecular Reassessment of Introgression Among Annual Helianthus Species (Asteraceae)

近50年来，植物基因渗入在植物进化中的作用一直是人们关注和推测的主题。基因渗入是指基因通过杂交和反复回交从一个物种转移到另一个物种。渗入的经典例子使用形态特征作为这一过程的证据。由于难以从特定基因的角度解释形态数据，这些研究仅提供了对植物遗传渗入作为一种进化机制的重要性的初步估计。Loren Rieseberg博士将应用强大的蛋白质和DNA分析的新分子方法来测量假定杂交植物种群和物种之间的基因流动。向日葵一年生植物Helianthus是研究植物基因渗入的理想类群，因为这些植物已有广泛的形态学和细胞学数据。此外，进化论者经常引用这个群体的成员作为遗传渐渗的杰出例子。Rieseberg博士项目的目标是：1)利用蛋白质（等位酶）和DNA证据确定一年生向日葵基因渗入的重要性；2)构建了向日葵科11种植物的dna系统发育模型；3)建立植物基因渗入分子分析的一般方法。

The role of introgression in plant evolution has been the subject of intense interest and speculation for over fifty years. Introgression is the transfer of genes from one species to another through hybridization and repeated backcrossing. The classic examples of introgression have used morphological features as evidence of this process. Because of difficulties interpreting morphological data in terms of specific genes, these studies have provided only tentative estimates of the significance of introgression as an evolutionary mechanism in plants. Dr. Loren Rieseberg will apply powerful new molecular methods of protein and DNA analyses to measure gene flow among populations and species of presumptively hybridizing plants. The annual species of sunflower, Helianthus, are an ideal group for studying introgression because of the extensive morphological and cytological data base already available for these plants. Furthermore, evolutionists frequently cite members of this group as outstanding examples of introgression. The objectives of Dr. Rieseberg's project are: 1) to determine the significance of introgression among the annual sunflowers using protein (allozyme) and DNA evidence; 2) to construct a DNA-based phylogeny for the 11 species of section Helianthus; and 3) to establish a general methodology for the molecular analysis of introgression in plants.