Robles P, Roig I, Garcia R, Brieño M, Martin M, Barbero J L, Cabero L I, Garcia-Caldés M
Departament de Biologia Cellular, Fisiologia i Immunologia, Universitat Autònoma de Barcelona, 08193, Bellaterra, Spain.
Reprod Biomed Online. 2009 Jun;18(6):784-94. doi: 10.1016/s1472-6483(10)60027-2.
It is accepted that recombination errors during human female meiotic prophase have some influence on the origin of trisomy 21. A total of 335 oocytes from four euploid fetuses were analysed by immunofluorescence and fluorescence in-situ hybridization in order to assess the recombination nodules along chromosome 21. Results based on the analysis of recombination points on the bivalent 21 during human female meiosis showed that both number [none (3.70%), one (79.01%) and two (17.29%)1 and distribution (always positioned interstitially on the q-arm) are different in males, ensuring that the two homologues more efficiently remain together until anaphase 1.Therefore, the mainly maternal origin of trisomy 21 appears not be linked to the first stages of oocyte development during fetal life, and this leads to the suggestion that the influence of environmental factors on the segregation of chromosome 21 homologues in later meiotic stages could have a significant role in the predominant maternal origin of trisomy 21.
人们普遍认为，人类女性减数分裂前期的重组错误对21三体综合征的起源有一定影响。为了评估21号染色体上的重组结节，对来自四个整倍体胎儿的335个卵母细胞进行了免疫荧光和荧光原位杂交分析。基于对人类女性减数分裂过程中二价体21上重组点的分析结果表明，男性中二价体21上重组点的数量[无（3.70%）、一个（79.01%）和两个（17.29%）]和分布（总是位于q臂的中间位置）有所不同，这确保了两条同源染色体在减数第一次分裂后期之前能更有效地保持在一起。因此，21三体综合征主要源于母体这一现象似乎与胎儿期卵母细胞发育的早期阶段无关，这表明环境因素对减数分裂后期21号染色体同源染色体分离的影响可能在21三体综合征主要源于母体这一现象中起重要作用。
