Abstract

Repetitive DNA is a rapidly evolving component of vascular plant genomes, which can account for genomic differentiation in plant lineages. Satellite DNA (satDNA) is tandem repetitive DNA for which array size and disposition on chromosomes may vary between reproductively isolated groups, such as different populations or closely related species. Deschampsia is a cosmopolitan grass genus growing in temperate and cold regions; D. cespitosa is widespread all over the world, whereas D. antarctica is restricted to Antarctica and southern Patagonia. The present work aims to the identification, isolation and comparison of satDNA from the genomes of two Deschampsia spp. with bioinformatics tools and their subsequent analysis and cytological study. The genomic analysis of TAREAN found 34 families of satDNA included on 21 superfamilies, most of them shared between the two species. Some of these satDNAs presented homology with others previously reported for grasses. A few satDNA families were found exclusively in one of the species. Most satDNAs were found in both species and showed high sequence homology, but their distribution on chromosomes was different between species. This highlights the importance of changes in the genomic disposition of satDNA in the evolution of species. Based on the ‘satDNA library hypothesis’ the differential amplification of satDNAs between independent lineages may be the cause of such differences.

中文翻译：

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基于卫星DNA的南极Deschampsia和D. cespitosa（禾本科）的基因组分化

摘要

重复DNA是维管束植物基因组的一个快速发展的成分，可以解释植物谱系中的基因组分化。卫星DNA（satDNA）是串联重复DNA，其染色体大小和排列在生殖分离群体（例如不同种群或紧密相关物种）之间可能会有所不同。德尚是一种在温带和寒冷地区生长的世界性草属。cespitosa D. cespitosa遍布世界各地，而南极D.只限于南极和巴塔哥尼亚南部。目前的工作旨在鉴定，分离和比较两个德尚的基因组中的satDNA。spp。生物信息学工具及其后续分析和细胞学研究。TAREAN的基因组分析发现21个超家族中包含34个satDNA家族，其中大多数在两个物种之间共享。其中一些satDNA与先前报道的其他草具有同源性。仅在一个物种中发现了几个satDNA家族。在两个物种中都发现了大多数satDNA，并显示出高序列同源性，但是它们在染色体上的分布在物种之间是不同的。这凸显了satDNA基因组配置变化在物种进化中的重要性。基于“ satDNA文库假说”，独立谱系之间satDNA的差异扩增可能是造成这种差异的原因。