maternal nondisjunction

Is Nondisjunction More Common In Meiosis I Or II?

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Is Nondisjunction More Common In Meiosis I Or II? Among the 188 maternal cases, nondisjunction occurred in meiosis I in 128 cases and in meiosis II in 38 cases; in 22 cases the DNA markers used were uninformative. Therefore meiosis I was responsible for 77.1% and meiosis II for 22.9% of maternal nondisjunction. Does nondisjunction

Is Trisomy 21 Caused By Nondisjunction?

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Is Trisomy 21 Caused By Nondisjunction? Down syndrome is usually caused by an error in cell division called “nondisjunction.” Nondisjunction results in an embryo with three copies of chromosome 21 instead of the usual two. Is trisomy 21 caused by meiosis? Maternal meiosis II nondisjunction in trisomy 21 is associated with maternal low socioeconomic status.