Evolution of Meiotic Mechanisms in Divergent Cytological Environments

描述（由申请人提供）：减数分裂是所有有性生殖生物的基本过程。这个过程中的问题可能导致染色体错误分离，这可能导致不育，致命性和疾病，如唐氏综合症。减数分裂的许多蛋白质和元件在进化上是保守的，在精确的减数分裂机制中存在物种水平的差异，但是关于这些不同机制或相关蛋白质如何进化的数据非常少。我建议通过研究密切相关的二倍体和同源四倍体拟南芥之间的细胞学和功能分子遗传差异来解决一个新的减数分裂过程和相关蛋白质如何演变的问题。多倍性是研究这个问题的理想系统，因为在同源染色体数目加倍的环境中，减数分裂机制存在强大的选择压力，以确保正确的配对、交换和分离。为了记录这些环境之间的差异，我建议对二倍体、天然同源四倍体和合成四倍体品系进行详细的细胞学调查。我还将通过转基因分析研究四倍体谱系中具有强烈选择特征的减数分裂相关蛋白的功能。在一个免费的实验中，我将进行人工选择实验的配子生活力在合成同源四倍体和遗传 绘制确保四倍体中正确减数分裂的基因座。

DESCRIPTION (provided by applicant): Meiosis is a fundamental process for all sexual reproducing organisms. Problems in this process can lead to chromosome mis-segregation, which can result in sterility, lethality, and diseases such as Down's syndrome. Many proteins and elements of meiosis are evolutionarily conserved, there is species level variation in the precise meiotic mechanisms, but there is remarkably little data on how these different mechanisms or the associated proteins have evolved. I propose to address the question of how a novel meiotic process and associated proteins evolve by studying cytological and functional molecular genetic differences between closely related diploid and autotetraploid Arabidopsis arenosa. Polyploidy is an ideal system to study this question, because there is strong selective pressure on the meiosis machinery to ensure proper pairing, crossing- over, and segregation in an environment with double the number of homologous chromosomes. To catalogue the differences between these environments, I propose to conduct a detailed cytological investigation of diploid, natural autotetraploid, and synthetic tetraploid lines. I will also investigate the function of meiosis related proteins with strong signatures of selection in the tetraploid lineage through transgenic analysis. In a complimentary experiment, I will conduct an artificial selection experiment on gamete viability in the synthetic autotetraploid and genetically map loci that ensure proper meiosis in the tetraploid.