Commitment to X inactivation precedes the twinning event in monochorionic MZ twins
Commitment to X inactivation precedes the twinning event in monochorionic MZ twins
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DOI：
10.1086/301978
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发表时间：
1998-08-01
影响因子：
9.8
通讯作者：
Gregersen, PK
中科院分区：
文献类型：
--
作者：
Monteiro, J;Derom, C;Gregersen, PK
为了深入了解双胞胎的时间，我们检查了女性同卵双胞胎中一个密切相关的事件，即 X 染色体失活。比较单绒毛膜同卵双胞胎 (MC-MZ) 和双绒毛膜同卵双胞胎 (DC-MZ) 外周血和颊粘膜的 X 失活模式。总体而言，当对两种组织进行测试时，MC-MZ 双胞胎表现出高度相似的 X 失活模式，而 DC-MZ 双胞胎的 X 失活模式经常不同。先前的实验数据表明，当胚胎中有 10-20 个细胞时，就会发生 X 失活。对 X 失活后胚胎分裂的模拟表明，MC-MZ 孪生在 X 失活后发生三轮或四轮复制，而 DC-MZ 孪生事件发生在 X 失活之前、之前或前后。最后，同卵双胞胎的总体偏斜程度与单胞胎中观察到的总体偏斜程度没有显着差异。这表明X失活在孪生过程中并不发挥直接作用，并且进一步表明极端不等分裂并不是孪生形成的常见机制。
To gain insight into the timing of twinning, we have examined a closely related event, X-chromosome inactivation, in female MZ twin pairs. X-inactivation patterns in peripheral blood and buccal mucosa were compared between monochorionic MZ (MC-MZ) and dichorionic MZ (DC-MZ) twins. Overall, the MC-MZ twins displayed highly similar X-inactivation patterns, whereas DC-MZ twins frequently differed in their X-inactivation patterns, when both tissues were tested. Previous experimental data suggest that commitment to X inactivation occurs when there are 10-20 cells in the embryo. Simulation of embryo splitting after commitment to X inactivation suggests that MC-MZ twinning occurs three or four rounds of replication after X inactivation, whereas a DC-MZ twinning event occurs earlier, before or around the time of X inactivation. Finally, the overall degree of skewing in the MZ twins was not significantly different from that observed in singletons. This indicates that X inactivation does not play a direct role in the twinning process, and it further suggests that extreme unequal splitting is not a common mechanism of twin formation.