Giulotto Elena, Raimondi Elena, Sullivan Kevin F
Dipartimento di Biologia e Biotecnologie, Università di Pavia, Via Ferrata 1, 27100, Pavia, Italy.
National University of Ireland Galway, University Road, Galway, Ireland.
Prog Mol Subcell Biol. 2017;56:337-354. doi: 10.1007/978-3-319-58592-5_14.
Centromeres are highly distinctive genetic loci whose function is specified largely by epigenetic mechanisms. Understanding the role of DNA sequences in centromere function has been a daunting task due to the highly repetitive nature of centromeres in animal chromosomes. The discovery of a centromere devoid of satellite DNA in the domestic horse consolidated observations on the epigenetic nature of centromere identity, showing that entirely natural chromosomes could function without satellite DNA cues. Horses belong to the genus Equus which exhibits a very high degree of evolutionary plasticity in centromere position and DNA sequence composition. Examination of horses has revealed that the position of the satellite-free centromere is variable among individuals. Analysis of centromere location and composition in other Equus species, including domestic donkey and zebras, confirms that the satellite-less configuration of centromeres is common in this group which has undergone particularly rapid karyotype evolution. These features have established the equids as a new mammalian system in which to investigate the molecular organization, dynamics and evolutionary behaviour of centromeres.
着丝粒是高度独特的基因位点，其功能很大程度上由表观遗传机制决定。由于动物染色体着丝粒具有高度重复性，了解DNA序列在着丝粒功能中的作用一直是一项艰巨的任务。在家马中发现不含卫星DNA的着丝粒，巩固了关于着丝粒身份表观遗传性质的观察结果，表明完全天然的染色体可以在没有卫星DNA线索的情况下发挥功能。马属于马属，在着丝粒位置和DNA序列组成方面表现出非常高的进化可塑性。对马的研究表明，无卫星着丝粒的位置在个体之间是可变的。对包括家驴和斑马在内的其他马属物种的着丝粒位置和组成进行分析，证实着丝粒无卫星的构型在这一经历了特别快速核型进化的群体中很常见。这些特征使马科动物成为研究着丝粒分子组织、动态和进化行为的新哺乳动物系统。
