Hamers A J, Meyer H, Jongbloed R J, van der Hulst R R, Geraedts J P
Department of Genetics and Cell Biology, University of Limburg, Maastricht, The Netherlands.
Clin Genet. 1990 Jun;37(6):463-9. doi: 10.1111/j.1399-0004.1990.tb03531.x.
To test the hypothesis of reduced chiasma frequency causing nondisjunction during meiosis, we examined 34 Down syndrome patients and their parents. Chromosomal polymorphisms and RFLP markers were used to trace the parental origin as well as the frequency of recombination of chromosomes 21. In all but one case, the parental origin and the meiotic stage of nondisjunction could be established by either technique. In 11 cases recombination could be deduced to have taken place during meiosis in the parent who contributed the extra chromosome 21. Because of the underestimation which is inherent in the methods used, these results do not seem to support the chiasma theory.
为了验证减数分裂过程中交叉频率降低导致不分离这一假说，我们研究了34名唐氏综合征患者及其父母。利用染色体多态性和限制性片段长度多态性（RFLP）标记来追踪21号染色体的亲本来源以及重组频率。除了1例之外，通过这两种技术均可确定不分离的亲本来源和减数分裂阶段。在11例中，可以推断出在贡献额外21号染色体的亲本减数分裂过程中发生了重组。由于所用方法存在固有的低估情况，这些结果似乎并不支持交叉理论。
