Chromosomal Evolution, Genetic Diversity, and Speciation Mechanisms in Polyploid Tragopogon (Asteraceae)

多倍体或全基因组复制是有花植物进化的主要力量，许多有花植物物种是通过杂交和多倍体的组合过程起源的。染色体变化可能通过多倍体中基因的丢失和复制产生遗传多样性，并可能促进物种形成，但在年轻的自然发生的多倍体植物中染色体进化的程度尚不清楚。本研究将利用分子细胞遗传学方法研究大黄草和小黄草的染色体和基因组变化。向日葵科的杂菜。 这些物种最近（在过去的80年里）通过亲本物种的不同种群的杂交而反复形成。 此外，这两个多倍体的合成系已经在实验室中产生。因此，Tragopogon提供了一个独特的机会，比较年轻的自然和合成多倍体植物的染色体变异。本项目将探讨新的多倍体中染色体变异的程度，是否有某些“规则”控制发生的变化类型，以及这种变异在自然种群中的影响。多倍体在开花植物中很常见（一组30万或更多的物种）。 此外，世界上所有的主要作物和最严重的杂草都是多倍体。 因此，描述多倍体形成后不久发生的过程对于了解大多数植物物种的基因组至关重要，因此对于我们保护植物生物多样性并可持续地从中受益的能力至关重要。结合DNA序列分析，该项目将在染色体，基因组和遗传水平上对多倍体化过程提供新的见解。

Polyploidy, or whole genome duplication, is a major force in flowering plant evolution, with many flowering plant species having originated through the combined processes of hybridization and polyploidy. Chromosomal changes may generate genetic diversity via loss and duplication of genes in polyploids and may promote speciation, but the extent of chromosomal evolution in young, naturally occurring polyploid plants is unknown. Molecular cytogenetic methods will be used to investigate chromosomal and genomic changes in Tragopogon mirus and T. miscellus of the sunflower family. These species formed recently (in the past 80 years) and repeatedly through hybridization of different populations of the parental species. Furthermore, synthetic lines of both polyploids have been produced in the lab. Tragopogon therefore provides a unique opportunity to compare chromosomal variation in young natural and synthetic polyploid plants. This project will address the extent of chromosomal variation in new polyploids, whether or not certain "rules" govern the types of changes that occur, and the effect of this variation in natural populations. Polyploidy is common in flowering plants (a group of 300,000 or more species). Furthermore, all of the world's major crops and most serious weeds are polyploid. Therefore, characterizing the processes that take place shortly after polyploid formation is crucial for understanding the genomes of most plant species, and thus for our ability to conserve plant biodiversity and sustainably benefit from it. In conjunction with DNA sequence analyses, this project will provide new insight into the process of polyploidization at the chromosomal, genomic, and genetic levels.