Jagannathan Madhav, Warsinger-Pepe Natalie, Watase George J, Yamashita Yukiko M
Howard Hughes Medical Institute, University of Michigan, Ann Arbor, Michigan 48109.
Life Sciences Institute, University of Michigan, Ann Arbor, Michigan 48109.
G3 (Bethesda). 2017 Feb 9;7(2):693-704. doi: 10.1534/g3.116.035352.
Satellite DNAs are highly repetitive sequences that account for the majority of constitutive heterochromatin in many eukaryotic genomes. It is widely recognized that sequences and locations of satellite DNAs are highly divergent even in closely related species, contributing to the hypothesis that satellite DNA differences may underlie speciation. However, due to its repetitive nature, the mapping of satellite DNAs has been mostly left out of recent genomics analyses, hampering the use of molecular genetics techniques to better understand their role in speciation and evolution. Satellite DNAs are most extensively and comprehensively mapped in , a species that is also an excellent model system with which to study speciation. Yet the lack of comprehensive knowledge regarding satellite DNA identity and location in its sibling species (, , and ) has prevented the full utilization of in studying speciation. To overcome this problem, we initiated the mapping of satellite DNAs on the genomes of the species complex (, , , and ) using multi-color fluorescent hybridization (FISH) probes. Our study confirms a striking divergence of satellite DNAs in the species complex, even among the closely related species of the clade (, , and ), and suggests the presence of unidentified satellite sequences in these species.
卫星DNA是高度重复序列,在许多真核生物基因组中占组成型异染色质的大部分。人们普遍认为,即使在亲缘关系密切的物种中,卫星DNA的序列和位置也存在高度差异,这支持了卫星DNA差异可能是物种形成基础的假说。然而,由于其重复性质,卫星DNA的定位在最近的基因组分析中大多被忽略,这阻碍了利用分子遗传学技术更好地理解它们在物种形成和进化中的作用。卫星DNA在[物种名称]中得到了最广泛和全面的定位,该物种也是研究物种形成的优秀模型系统。然而,由于缺乏关于其姊妹物种([姊妹物种名称1]、[姊妹物种名称2]和[姊妹物种名称3])中卫星DNA身份和位置的全面知识,妨碍了在研究物种形成时充分利用[物种名称]。为了克服这个问题,我们使用多色荧光原位杂交(FISH)探针,启动了对[物种复合体名称]([物种1名称]、[物种2名称]、[物种3名称]和[物种4名称])基因组中卫星DNA的定位。我们的研究证实了[物种复合体名称]中卫星DNA的显著差异,即使在[类群名称]的亲缘关系密切的物种([物种1名称]、[物种2名称]和[物种3名称])之间也是如此,并表明这些物种中存在未鉴定的卫星序列。