Watson J M, Spencer J A, Graves J A, Snead M L, Lau E C
Department of Genetics and Human Variation, La Trobe University, Bundoora, Victoria, Australia.
Genomics. 1992 Nov;14(3):785-9. doi: 10.1016/s0888-7543(05)80187-9.
We have determined by Southern blot analysis that DNA sequences homologous to the AMG gene probe are present in the genomes of both marsupial and monotreme mammals, although adult monotremes lack teeth. In situ hybridization and Southern analysis of cell hybrids demonstrate that AMG homologues are located on autosomes. In the Tammar Wallaby, AMG homologues are located on chromosomes 5q and 1q and in the Platypus, on chromosomes 1 and 2. The autosomal location of the AMG homologues provides additional support for the hypothesis that an autosomal region equivalent to the human Xp was translocated to the X chromosome in the Eutheria after the divergence of the marsupials 150 million years ago. The region containing the AMG gene is therefore likely to have been added 80-150 million years ago to a pseudoautosomal region shared by the ancestral eutherian X and Y chromosome; the X and Y alleles must have begun diverging after this date.
我们通过Southern印迹分析确定，与AMG基因探针同源的DNA序列存在于有袋类和单孔类哺乳动物的基因组中，尽管成年单孔类动物没有牙齿。细胞杂交的原位杂交和Southern分析表明，AMG同源物位于常染色体上。在帚尾袋鼩中，AMG同源物位于5号染色体长臂和1号染色体上，在鸭嘴兽中，位于1号和2号染色体上。AMG同源物的常染色体定位为以下假说提供了额外支持：在1.5亿年前有袋类动物分化后，相当于人类Xp的常染色体区域在真兽亚纲中易位到了X染色体上。因此，包含AMG基因的区域可能在8000万至1.5亿年前被添加到了祖先真兽亚纲X和Y染色体共享的拟常染色体区域；X和Y等位基因一定是在这个时间点之后开始分化的。
