Department of Biology, University of Texas at Arlington, Arlington, TX.
Mol Biol Evol. 2021 Mar 9;38(3):904-910. doi: 10.1093/molbev/msaa253.
Microchromosomes are common yet poorly understood components of many vertebrate genomes. Recent studies have revealed that microchromosomes contain a high density of genes and possess other distinct characteristics compared with macrochromosomes. Whether distinctive characteristics of microchromosomes extend to features of genome structure and organization, however, remains an open question. Here, we analyze Hi-C sequencing data from multiple vertebrate lineages and show that microchromosomes exhibit consistently high degrees of interchromosomal interaction (particularly with other microchromosomes), appear to be colocalized to a common central nuclear territory, and are comprised of a higher proportion of open chromatin than macrochromosomes. These findings highlight an unappreciated level of diversity in vertebrate genome structure and function, and raise important questions regarding the evolutionary origins and ramifications of microchromosomes and the genes that they house.
微染色体是许多脊椎动物基因组中常见但了解甚少的组成部分。最近的研究表明，微染色体含有高密度的基因，并具有与大染色体不同的其他特征。然而，微染色体的独特特征是否延伸到基因组结构和组织的特征仍然是一个悬而未决的问题。在这里，我们分析了来自多个脊椎动物谱系的 Hi-C 测序数据，结果表明微染色体表现出一致的高水平的染色体间相互作用（特别是与其他微染色体），似乎被局部定位到一个共同的中央核区域，并包含比大染色体更高比例的开放染色质。这些发现强调了脊椎动物基因组结构和功能多样性的一个未被认识的水平，并提出了关于微染色体及其所包含基因的进化起源和后果的重要问题。
