Prakash B, Olsaker I, Gustavsson I, Chowdhary B P
Department of Animal Breeding and Genetics, Swedish University of Agricultural Sciences, Uppsala, Sweden.
Hereditas. 1997;126(2):115-9. doi: 10.1111/j.1601-5223.1997.00115.x.
Contrary to extensive banding similarities of the autosomes, there are variations in the morphology as well as banding patterns of the X chromosomes of various species of bovidae family. We used three bovine X chromosome specific cosmid clones for fluorescence in situ hybridization mapping on cattle, goat, sheep, and river buffalo chromosomes to identify homologous regions in the genomes of the four species. The three cosmids (cIOBT 314, 945, and 1489) mapped to well spaced locations on buffalo X, and both arms of cattle X chromosome. However, of the three probes, cosmids cIOBT 314 and 1489 showed no hybridization signal on any of the goat-sheep chromosomes. Incidentally, the two cosmids show correspondence to those regions of the buffalo X chromosome which are proposed to be lost during the structural reshuffle of the latter, leading to sheep/goat X chromosomes. The lack of hybridization signal of the two cosmids in sheep and goat, therefore, indicates that these DNA sequences are most likely absent in the two genomes and probably correspond to the segments lost during evolution of their X chromosomes.
与常染色体广泛的带型相似性相反，牛科动物不同物种的X染色体在形态以及带型模式上存在差异。我们使用了三个牛X染色体特异性黏粒克隆，对牛、山羊、绵羊和水牛的染色体进行荧光原位杂交定位，以确定这四个物种基因组中的同源区域。这三个黏粒（cIOBT 314、945和1489）定位在水牛X染色体以及牛X染色体的两条臂上间隔良好的位置。然而，在这三个探针中，黏粒cIOBT 314和1489在任何山羊-绵羊染色体上均未显示杂交信号。顺便提一下，这两个黏粒与水牛X染色体的那些区域相对应，这些区域被认为在后者的结构重排过程中丢失，从而形成了绵羊/山羊的X染色体。因此，这两个黏粒在绵羊和山羊中缺乏杂交信号，表明这些DNA序列很可能在这两个基因组中不存在，并且可能对应于它们X染色体进化过程中丢失的片段。
