Wilcox S A, Watson J M, Spencer J A, Graves J A
School of Genetics and Human Variation, La Trobe University, Melbourne, Victoria, 3083, Australia.
Genomics. 1996 Jul 1;35(1):66-70. doi: 10.1006/geno.1996.0323.
Previous comparisons of gene location in the three major groups of mammals (eutherians, marsupials, and monotremes) have suggested that the long arm of the human X represents the ancestral mammalian X chromosome, whereas the short arm represents an autosomal region(s) recently added to the eutherian X chromosome. To identify the fusion point of this ancient X-autosome rearrangement, we have mapped four genes, three of which map near the centromere of the human Xp, in marsupials and in a monotreme. We found that ARAF1, ALAS2, and GATA1 are located on the X chromosome in marsupials, and ALAS2 and GATA1 are also located on the X in the platypus. This implies that the proximal short arm of the human X chromosome, including the centromere, was part of the ancestral mammalian X chromosome. The fusion point between the conserved region and the recently added regions therefore maps to human Xp11.23, although gene order on the human X indicates that there has been some rearrangement of this region.
先前对三大类哺乳动物（真兽类、有袋类和单孔类）基因定位的比较表明，人类X染色体的长臂代表了原始的哺乳动物X染色体，而短臂则代表了最近添加到真兽类X染色体上的一个常染色体区域。为了确定这种古老的X-常染色体重排的融合点，我们在有袋类动物和一种单孔类动物中对四个基因进行了定位，其中三个基因定位在人类Xp的着丝粒附近。我们发现，ARAF1、ALAS2和GATA1在有袋类动物中位于X染色体上，ALAS2和GATA1在鸭嘴兽中也位于X染色体上。这意味着人类X染色体的近端短臂，包括着丝粒，是原始哺乳动物X染色体的一部分。因此，保守区域和最近添加区域之间的融合点定位于人类Xp11.23，尽管人类X染色体上的基因顺序表明该区域发生了一些重排。
