群体间的重组图谱差异在驯化黑麦中表现为更大的低重组区域。
Recombination landscape divergence between populations is marked by larger low-recombining regions in domesticated rye.
作者信息
Schreiber Mona, Gao Yixuan, Koch Natalie, Fuchs Joerg, Heckmann Stefan, Himmelbach Axel, Börner Andreas, Özkan Hakan, Maurer Andreas, Stein Nils, Mascher Martin, Dreissig Steven
机构信息
University of Marburg, Department of Biology, Marburg, Germany.
Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), Seeland, OT Gatersleben, Germany.
出版信息
Mol Biol Evol. 2022 Jun 11;39(6). doi: 10.1093/molbev/msac131.
The genomic landscape of recombination plays an essential role in evolution. Patterns of recombination are highly variable along chromosomes, between sexes, individuals, populations, and species. In many eukaryotes, recombination rates are elevated in sub-telomeric regions and drastically reduced near centromeres, resulting in large low-recombining (LR) regions. The processes of recombination are influenced by genetic factors, such as different alleles of genes involved in meiosis and chromatin structure, as well as external environmental stimuli like temperature and overall stress. In this work, we focused on the genomic landscapes of recombination in a collection of 916 rye (Secale cereale) individuals. By analysing population structure among individuals of different domestication status and geographic origin, we detected high levels of admixture, reflecting the reproductive biology of a self-incompatible, wind-pollinating grass species. We then analysed patterns of recombination in overlapping subpopulations, which revealed substantial variation in the physical size of LR regions, with a tendency for larger LR regions in domesticated subpopulations. Genome-wide association scans (GWAS) for LR region size revealed a major quantitative-trait-locus (QTL) at which, among 18 annotated genes, an ortholog of histone H4 acetyltransferase ESA1 was located. Rye individuals belonging to domesticated subpopulations showed increased synaptonemal complex length, but no difference in crossover frequency, indicating that only the recombination landscape is different. Furthermore, the genomic region harbouring rye ScESA1 showed moderate patterns of selection in domesticated subpopulations, suggesting that larger LR regions were indirectly selected for during domestication to achieve more homogeneous populations for agricultural use.
重组的基因组格局在进化中起着至关重要的作用。重组模式在染色体上、性别之间、个体之间、种群之间以及物种之间高度可变。在许多真核生物中,亚端粒区域的重组率升高,而着丝粒附近则急剧降低,从而形成大片低重组(LR)区域。重组过程受遗传因素影响,如参与减数分裂和染色质结构的基因的不同等位基因,以及温度和整体应激等外部环境刺激。在这项研究中,我们聚焦于916个黑麦(Secale cereale)个体群体中的重组基因组格局。通过分析不同驯化状态和地理起源个体之间的种群结构,我们检测到高度的混合,这反映了一种自交不亲和、风媒传粉禾本科物种的生殖生物学特性。然后,我们分析了重叠亚群中的重组模式,结果显示LR区域的物理大小存在显著差异,驯化亚群中的LR区域有更大的趋势。对LR区域大小进行全基因组关联扫描(GWAS)发现了一个主要的数量性状位点(QTL),在18个注释基因中,组蛋白H4乙酰转移酶ESA1的一个直系同源基因位于该位点。属于驯化亚群的黑麦个体显示联会复合体长度增加,但交叉频率没有差异,这表明只有重组格局不同。此外,包含黑麦ScESA1的基因组区域在驯化亚群中表现出适度的选择模式,这表明在驯化过程中,较大的LR区域被间接选择,以获得更均匀的用于农业的群体。