Derom C, Bakker E, Vlietinck R, Derom R, Van den Berghe H, Thiery M, Pearson P
J Med Genet. 1985 Aug;22(4):279-82. doi: 10.1136/jmg.22.4.279.
A prerequisite for the optimal use of the twin method in human genetics is an accurate determination of the zygosity at birth. This diagnosis is sometimes hampered by the lack of available specific markers. We report here the use of DNA variants (restriction fragment length polymorphisms) as genetic markers for zygosity determination. We have analysed the placental DNA of 22 twin pairs with known zygosity on Southern blots by hybridisation with polymorphic human DNA probes. We looked at six different polymorphic sites using four restriction enzymes and six DNA probes. Among 10 dizygotic (DZ) pairs, only one was not demonstrably different and seven had at least two discordances. Within each of the 12 monozygotic (MZ) pairs there was complete concordance. Thus, nine of 10 dizygotic and 12 of 12 monozygotic twins were assigned their correct zygosity solely by comparison of six DNA variants. The use of these highly polymorphic DNA probes may have practical importance for antenatal diagnosis and paternity testing.
在人类遗传学中最佳运用双生子法的一个前提条件是在出生时准确确定合子性。这种诊断有时会因缺乏可用的特定标记而受阻。我们在此报告使用DNA变异（限制性片段长度多态性）作为确定合子性的遗传标记。我们通过与多态性人类DNA探针杂交，在Southern印迹上分析了22对已知合子性的双生子胎盘DNA。我们使用四种限制性内切酶和六种DNA探针研究了六个不同的多态性位点。在10对异卵双生子（DZ）中，只有一对没有明显差异，七对至少有两个不一致之处。在12对同卵双生子（MZ）的每一对中都完全一致。因此，仅通过比较六个DNA变异，10对异卵双生子中的9对和12对同卵双生子中的12对都被正确确定了合子性。这些高度多态性DNA探针的使用可能在产前诊断和亲子鉴定中具有实际重要性。
