Allen W R, Skidmore J A, Stewart F, Antczak D F
Thoroughbred Breeders' Association Equine Fertility Unit, Mertoun Paddocks, Newmarket, Suffolk, UK.
J Reprod Fertil. 1993 May;98(1):55-60. doi: 10.1530/jrf.0.0980055.
Measurement of the concentrations of equine chorionic gonadotrophin (eCG) in the serum of pregnant mares and Jenny donkeys carrying normal intraspecies and hybrid interspecies pregnancies suggested that the production of this hormone may be influenced by parental gene imprinting. Specifically, a differential expression of maternal and paternal genes may control the size and secretory activity of the structures that secrete eCG, the fetal endometrial cups. However, bisection of an interspecies mule embryo followed by transfer of the resulting demi-embryos and other intact mule embryos to horse and donkey recipients resulted in striking differences in the size, secretory activity and lifespan of the endometrial cups in two types of surrogate mother. This finding has therefore demonstrated the ability of uterine factors to alter profoundly the development and characteristic phenotype of the specialized invasive chorionic girdle portion of the equine trophoblast that gives rise to the endometrial cups.
对怀有正常种内和种间杂交妊娠的怀孕母马和珍妮驴血清中马绒毛膜促性腺激素（eCG）浓度的测量表明，这种激素的产生可能受亲本基因印记的影响。具体而言，母源和父源基因的差异表达可能控制分泌eCG的结构即胎儿子宫内膜杯的大小和分泌活性。然而，将种间骡胚胎一分为二，然后将得到的半胚胎和其他完整的骡胚胎移植到马和驴受体中，结果发现两种类型的代孕母体中子宫内膜杯的大小、分泌活性和寿命存在显著差异。因此，这一发现证明了子宫因素能够深刻改变马滋养层特化侵袭性绒毛带部分的发育和特征表型，而该部分会形成子宫内膜杯。
