When sex may or may not happen – The impact of asymmetrical meiosis on the evolutionary fate of genes in polyploid roses

玫瑰是一个具有广泛杂交和多倍体的重要生态属。此外，欧洲狗狗在其独特的半性生殖中是神秘的：由于它们的不对称减数分裂（犬减数分裂），它们在同一个细胞核中结合了有性和无性生殖的特征。本研究拟通过对蔷薇基因组的研究，探讨犬系减数分裂的起源、对染色体的差异影响以及与全有性系蔷薇物种的进化突变负荷。通过比较基因组学，我们将追踪二倍体玫瑰对现代多倍体基因组的各自贡献，并确定半性和有性物种中单拷贝基因的等位基因差异。此外，我们将开发新的细胞遗传学标记来阐明不对称减数分裂的不同阶段及其可能的表观遗传控制。我们的目标将通过应用先进的计算方法来解决，这些方法允许使用系统发育和群体遗传方法对核单拷贝基因进行全基因组分析。实验还将涉及荧光原位杂交（FISH），染色质免疫沉淀和组织化学标记。

Rosa represents an ecologically important genus with widespread hybridization and polyploidy. Moreover, the European dogroses are enigmatic in having a unique hemisexual reproduction: due to their asymmetrical meiosis (Canina meiosis) they combine features of both sexual and asexual reproduction in the same nucleus. Here we propose to explore Rosa genomes to investigate the origin of the Canina meiosis, its differential effects on chromosome and evolution mutational load compared to fully sexual rose species. Through comparative genomics we will trace the respective contributions of diploid roses to the genome of modern polyploids and determine allelic divergence of single copy genes in hemisexual and sexual species. In addition we will develop new cytogenetic markers to elucidate different phases of asymmetrical meiosis and their putative epigenetic control. Our aims will be tackled by the application of advanced computational methods allowing genome wide analyses of nuclear single copy genes using phylogenetic and population genetic approaches. Experiments will also involve Fluorescence-in-situ-Hybridization (FISH), chromatin immunoprecipitation and -histochemical labelling.