Dickinson D G, Baker R F
Proc Natl Acad Sci U S A. 1978 Nov;75(11):5627-30. doi: 10.1073/pnas.75.11.5627.
Hairpin-like DNA was prepared in vitro from the family of sequences that are inverted relative to each other and, as pairs, are relatively homologous and adjacent on the sea urchin genome. The majority of these hairpins are shown to have base pair mismatch positions distributed along their stems. Comparison of the hairpins derived from the DNA of morula, blastula, and gastrula stage embryos shows that during embryogenesis there are changes in the average number and position of S1 nuclease-sensitive base pair mismatch sites on the majority of the hairpin stems. Our data indicate that during early embryogenesis there are sequence changes in vivo within the majority of the adjacent inverted repeat sequences of the sea urchin genome. We have also found that there is higher specificity for the occurrence of sequence-change events within that fraction of the inverted repeat sequences that are methylated in vivo.
发夹状DNA是在体外从彼此反向、作为对在海胆基因组上相对同源且相邻的序列家族制备的。这些发夹中的大多数显示其碱基对错配位置沿其茎分布。对来自桑椹胚、囊胚和原肠胚阶段胚胎DNA的发夹进行比较表明，在胚胎发生过程中，大多数发夹茎上S1核酸酶敏感碱基对错配位点的平均数量和位置发生了变化。我们的数据表明，在早期胚胎发生过程中，海胆基因组中大多数相邻反向重复序列在体内发生了序列变化。我们还发现，在体内发生甲基化的那部分反向重复序列内，序列变化事件的发生具有更高的特异性。
