Plante Y, Schmutz S M, Lang K D, Moker J S
DNA Laboratory, Saskatchewan Research Council, Saskatoon, Canada.
Anim Genet. 1992;23(4):295-302. doi: 10.1111/j.1365-2052.1992.tb00151.x.
Karyotyping and hypervariable genetic markers indicate extensive leucochimaerism between pairs of dizygotic twins in cattle, a result of placental vascular anastomosis. The extent of this chimaerism includes both kind and number of cells exchanged. All heterosexual twin pairs harboured two types of leucocytes, having either XX or XY chromosome pairs, and 30 of 31 pairs of twins shared identical DNA fingerprints. Although chromosome results from skin fibroblasts indicate that some chimaerism occurs in the skin, the low level allows for differentiation of genotypes between twins. The results warrant against the common practice of using blood samples for DNA typing if twinning is not properly documented.
核型分析和高变遗传标记表明，牛的双合子双胞胎之间存在广泛的白细胞嵌合体现象，这是胎盘血管吻合的结果。这种嵌合体的程度包括交换细胞的种类和数量。所有异性双胞胎对都含有两种类型的白细胞，其染色体对分别为XX或XY，并且31对双胞胎中有30对具有相同的DNA指纹。尽管皮肤成纤维细胞的染色体结果表明皮肤中存在一些嵌合体现象，但低水平的嵌合体现象使得双胞胎之间的基因型能够得以区分。如果双胞胎情况没有得到妥善记录，这些结果警示了使用血样进行DNA分型的常见做法。
