Shcherbakov V P, Toompuu O G
Genetika. 1977;13(8):1409-24.
Formal genetic consequences of generation and break-up of a half chromatid chiasma have been studied on the basis of a model with the symmetric exchange of two strands between parental DNA molecules. In recombination analysis, generation and break-up of this structure gives rise to a critical frequency R (zeta), which corresponds to recombination between two markers separated by a distance equal to the mean genetic length zeta of the hybrid region at the time of scission of the cross connection. The use of the distance zata as a natural unit of a genetic map is suggested. In the case of bacteriophage T4 under conditions of standard crosses the half chromatid chiasma is characterized by the value R (zata) equal to 3.0-10(-2), the structure acquiring with equal probability either of the two alternative isomeric configurations at the time of scission of the cross connection. About four per cent of the total number of mismatches as a result of break-up to the half chromatid chiasm were repaired.
基于亲代DNA分子间两条链对称交换的模型，对半染色单体交叉的产生和断裂的形式遗传学后果进行了研究。在重组分析中，这种结构的产生和断裂会产生一个临界频率R（ζ），它对应于两个标记之间的重组，这两个标记之间的距离等于交叉连接断裂时杂交区域的平均遗传长度ζ。建议使用距离ζ作为遗传图谱的自然单位。在标准杂交条件下的噬菌体T4的情况下，半染色单体交叉的特征是R（ζ）值等于3.0 - 10^(-2)，在交叉连接断裂时，该结构以相等的概率获得两种替代的异构构型中的任何一种。由于半染色单体交叉断裂而产生的错配总数中约有4%得到了修复。
