六例X染色体结构异常的RFLP研究

MOLECULAR STUDY OF X CHROMOSOME STRUCTURAL ABNORMALITIES

利用9个定位于X染色体长、短臂上的DNA探针,以限制性片段长度多态性(RFLPS)作为遗传标记,对8例X结构异常患者及其家系进行了分子遗传学研究,以探讨其起源和形成机理。经基因分离分析和基因剂量分析证明,dup(Xp),del(Xp)及r(X)分别源自父方精子形成过程中X染色体的一次姊妹染色单体不等交换、X染色体断裂、缺失或X染色体断裂、重接,而i(Xq)则源自母方卵子形成过程中X染色体发生错分裂的结果。

Parental origin and mechanism of formation of X chromosome structural abnormalities were studied in 6 cases and their parents using RFLP as genetic markers. The results suggest that dup (Xp) is due to events involving an unequal exchange between sister chromatid during spermatogenesis; del (Xp) arise from a simple breakage and deletion, and r(X) arises from a breakage-reunion events during spermatogenesis, while three i(Xq) are the results from X chromosome misdivision during oogenesis.