Lejeune J, Aurias A
Acta Genet Med Gemellol (Roma). 1976;25:50-2. doi: 10.1017/s0001566000013817.
Since the first publication in 1961, cases of monozygotic heterocaryotic twinning have been repeatedly found and a total of 14 observations can now be analysed. The mechanism involved in this type of twinning is yet uncertain and eventually is not identical in each case, the main uncertainty being to decide whether the chromosomal error affecting one of the twins is related, directly or indirectly, to the process of MZ twinning per se. Regarding the time of occurrence, the error seems to occur at few days of development at the most and, in one case at least, was contemporary to the first division cleavage. Considering the possibility of twins of different sex (e.g., one XY and one XO) the MZ heterocaryotic twinning could be considered as a potential equivalent of autofecundation in species in which the XO is a fertile female. Evolutive implications shall be discussed.
自1961年首次发表以来，已多次发现单卵异核孪生病例，目前总共可分析14例观察结果。这种孪生类型所涉及的机制尚不确定，而且在每种情况下最终都不相同，主要的不确定性在于确定影响其中一个双胞胎的染色体错误是否直接或间接地与单卵孪生过程本身相关。关于发生时间，这种错误似乎最多发生在发育的几天内，并且至少在一个案例中与第一次卵裂同时发生。考虑到不同性别的双胞胎（例如，一个XY和一个XO）的可能性，单卵异核孪生可被视为XO为可育雌性的物种中自体受精的潜在等效情况。将讨论其进化意义。
