很多流行病学资料表明,Down 综合征(47,+21)的出生率与母亲年龄有密切关系。人们对此提出了一个假设:即在新生儿中观察到的47,+21的增加,反映了妊娠中非整倍体胚胎的增加,而这些三体型的大多数是由母亲减数分裂中的失误引起的。近来,关于母亲的作用仅仅通过增加在第一次成熟分裂中染色体不分离的假设正在受到下列事实的挑战:第一,在47,+21的活婴中有20%的额外染色体来自父亲。第二,无论额外染色体来自父亲或来自母亲,母亲年龄的影响都存在。这个事实暗示一定还有 Many epidemiological data show that the birth rate of Down syndrome (47, +21) is closely related to the mother’s age. This led to the hypothesis that an increase in 47, +21, observed in newborns, reflects an increase in gestational aneuploid embryos, the majority of these trisomies being caused by meiosis Caused by mistakes Recently, the hypothesis that mothers are only contributing to the non-segregation of chromosomes at the first maturation stage is being challenged by the fact that first, 20% of extra chromosomes in 47 + 21 live babies come from fathers. Second, the effects of mother age exist whether extra chromosomes are from a father or from a mother. This fact suggests there must be