Watson J M, Spencer J A, Riggs A D, Graves J A
Department of Genetics and Human Variation, La Trobe University, Bundoora, Victoria, Australia.
Proc Natl Acad Sci U S A. 1991 Dec 15;88(24):11256-60. doi: 10.1073/pnas.88.24.11256.
To investigate the evolution of the mammalian sex chromosomes, we have compared the gene content of the X chromosomes in the mammalian groups most distantly related to man (marsupials and monotremes). Previous work established that genes on the long arm of the human X chromosome are conserved on the X chromosomes in all mammals, revealing that this region was part of an ancient mammalian X chromosome. However, we now report that several genes located on the short arm of the human X chromosome are absent from the platypus X chromosome, as well as from the marsupial X chromosome. Because monotremes and marsupials diverged independently from eutherian mammals, this finding implies that the whole human X short arm region is a relatively recent addition to the X chromosome in eutherian mammals.
为了研究哺乳动物性染色体的进化，我们比较了与人类亲缘关系最远的哺乳动物类群（有袋类动物和单孔目动物）中X染色体的基因含量。先前的研究表明，人类X染色体长臂上的基因在所有哺乳动物的X染色体上都是保守的，这表明该区域是古老哺乳动物X染色体的一部分。然而，我们现在报告称，人类X染色体短臂上的几个基因在鸭嘴兽的X染色体以及有袋类动物的X染色体上都不存在。由于单孔目动物和有袋类动物是从真兽类哺乳动物中独立分化出来的，这一发现意味着整个人类X染色体短臂区域是真兽类哺乳动物X染色体上相对较新添加的部分。
