Molecular Evolution of Floral Homeotic Genes in the Hawaiian Silversword Alliance (Asteraceae)

MADS-box调控基因家族代表了一组控制花发育关键方面的基因。这些发育控制基因的分子进化动力学仍然知之甚少。该项目旨在研究夏威夷银藻联盟（madinae, Asteraceae）中这个调节基因家族成员的分子进化，这是岛屿植物适应性辐射的首要例子。将利用分子技术从14个银藻联盟物种及其在加利福尼亚大陆的亲戚targrass中分离出3个花控制基因——APETALA1、APETALA3和AGAMOUS。对这些基因序列的分析将用于推断这些快速进化的分类群中基因进化的速率和模式，并将提供塑造这些调节位点多样化的进化力量的信息。该研究将评估与近期适应性多样化相关的花同源基因的变化动态，并可能导致新的核标记的开发，用于基于序列的低分类水平的植物系统发育研究。确定调控基因进化的模式和速度对于理解物种之间形态差异背后的遗传基础至关重要。在充分研究适应性辐射的背景下研究这些基因，可以更好地了解控制发育特征的基因如何在快速多样化的物种中进化。通过剖析这些控制基因进化背后的机制，有可能确定基因调控的变化对我们在自然界中看到的花结构多样性的影响程度。

9708540 Purugganan The MADS-box regulatory gene family represents a group of genes that control crucial aspects of flower development. The molecular evolutionary dynamics of these developmental control genes remain poorly understood. This project seeks to investigate the molecular evolution of members of this regulatory gene family in the Hawaiian silversword alliance (Madiinae, Asteraceae), the premier example of island plant adaptive radiation. Three floral control genes - APETALA1, APETALA3 and AGAMOUS - will be isolated by molecular techniques in 14 silversword alliance species and their mainland California relatives, the tarweeds. Analysis of these gene sequences will be used to infer the rates and patterns of gene evolution in these rapidly-evolving taxa, and will provide information on the evolutionary forces that shape the diversification of these regulatory loci. This study will assess the dynamics of change in floral homeotic genes associated with a recent adaptive diversification, and may lead to the development of new nuclear markers for use in sequence-based, plant phylogenetic studies at low taxonomic levels. Determining mode and tempo of regulatory gene evolution is vital to understanding the genetic basis behind differences in morphologies between species. Studying these genes in the context of a well-studied adaptive radiation permits a greater knowledge of how genes that control developmental traits evolve in rapidly diversifying species. By dissecting the mechanisms behind the evolution of these control genes, it may be possible to determine the extent to which changes in gene regulation contribute to the diversity in floral structures we see in the natural world.