Deuve J L, Bennett N C, O'Brien P C M, Ferguson-Smith M A, Faulkes C G, Britton-Davidian J, Robinson T J
Evolutionary Genetics Group, Department of Botany and Zoology, University of Stellenbosch, Private Bag X1, Matieland 7602, South Africa.
Chromosome Res. 2006;14(6):681-91. doi: 10.1007/s10577-006-1080-3. Epub 2006 Sep 14.
Cross-species chromosome painting was used to determine homologous chromosomal regions between two species of mole-rat, the naked mole-rat, Heterocephalus glaber (2n = 60), and the giant mole-rat, Cryptomys mechowi (2n = 40), using flow-sorted painting probes representative of all but two of the H. glaber chromosomal complement. In total 43 homologous regions were identified in the C. mechowi genome. Eight H. glaber chromosomes are retained in toto in C. mechowi, and 13 produce two or more signals in this species. The most striking difference in the karyotypes of the two taxa concerns their sex chromosomes. The H. glaber painting probes identified a complex series of translocations that involved the fractionation of four autosomes and the subsequent translocation of segments to the sex chromosomes and to autosomal partners in the C. mechowi genome. An intercalary heterochromatic block (IHB) was detected in sex chromosomes of C. mechowi at the boundary with the translocated autosomal segment. We discuss the likely sequence of evolutionary events that has led to the contemporary composition of the C. mechowi sex chromosomes, and consider these in the light of prevailing views on the genesis of sex chromosomes in mammals.
跨物种染色体描绘被用于确定裸鼹形鼠（Heterocephalus glaber，2n = 60）和巨鼹形鼠（Cryptomys mechowi，2n = 40）这两种鼹形鼠之间的同源染色体区域，使用代表除两条之外所有H. glaber染色体组的流式分选描绘探针。在C. mechowi基因组中总共鉴定出43个同源区域。在C. mechowi中完整保留了8条H. glaber染色体，并且有13条在该物种中产生两个或更多信号。这两个分类单元核型中最显著的差异涉及其性染色体。H. glaber描绘探针鉴定出一系列复杂的易位，这些易位涉及四条常染色体的断裂以及随后片段向C. mechowi基因组中的性染色体和常染色体伙伴的易位。在C. mechowi性染色体与易位常染色体片段的边界处检测到一个中间异染色质块（IHB）。我们讨论了导致C. mechowi性染色体当代组成的可能进化事件序列，并根据关于哺乳动物性染色体起源的主流观点来考虑这些事件。
