Consider the abbreviated model of meiosis. The end result of meiosis should be the production of four haploid gametes. In this example, an error has taken place. Describe and name this error.

Question

Responses
A Nondisjunction of sister chromatids during meiosis II. Sister chromatids fail to separate.Nondisjunction of sister chromatids during meiosis II. Sister chromatids fail to separate.
B Translocation of sister chromatids during meiosis II. One chromatid is translocated into incorrect cell.Translocation of sister chromatids during meiosis II. One chromatid is translocated into incorrect cell.
C Separation mutation during meiosis I. Resulting gametes in meiosis II have incorrect chromosome number at end of meiosis.Separation mutation during meiosis I. Resulting gametes in meiosis II have incorrect chromosome number at end of meiosis.
D Replication error during meiosis I. Results of mutation show during meiosis II as incorrect chromosome number in two gametes.Replication error during meiosis I. Results of mutation show during meiosis II as incorrect chromosome number in two gametes.

Answer 1

The correct option that describes the error during meiosis resulting in the incorrect number of gametes is:

A. Nondisjunction of sister chromatids during meiosis II. Sister chromatids fail to separate.

Nondisjunction is the failure of homologous chromosomes or sister chromatids to separate properly during cell division. In this case, if sister chromatids fail to separate during meiosis II, it can lead to gametes with an abnormal number of chromosomes. This is a common cause of genetic disorders and can result in conditions such as Down syndrome, where an individual has an extra copy of chromosome 21.