How do you know if Nondisjunction occurs in meiosis 1 or 2?
Also asked, is Nondisjunction more common in meiosis I or II?
Nondisjunction can occur either during meiosis I or meiosis II, but it is more common during meiosis I. If nondisjunction occurs, then the gametes will not contain the correct number of chromosomes; instead of a single copy, the gametes will either have two copies of a chromosome or no copies.
Similarly, in which parent did Nondisjunction occur? Explanation: Nondisjunction means nonseparation: of either homologous chromosome in meiosis I or of sister chromatids in meiosis II. In both the cases abnormal gametes will be formed and after fertilisation, there will be trisomy or monosomy of chromosome.
In respect to this, is Down syndrome caused by nondisjunction in meiosis 1 or 2?
Nondisjunction occurs when homologous chromosomes (meiosis I) or sister chromatids (meiosis II) fail to separate during meiosis. The most common trisomy is that of chromosome 21, which leads to Down syndrome.
Does Nondisjunction occur more in eggs or sperm?
The cause of nondisjunction is unknown. Nondisjunction seems to be a chance event. Nothing that a person does or doesn't do during their reproductive years can cause these chromosomal changes. We do know that nondisjunction occurs more frequently in the eggs of women as they get older.