Recall what you learned about the fate of homologous chromosomes during meiosis I and the sister chromatids during meiosis II, and explain how trisomies like trisomy 21 or poly-X syndrome could occur

During meiosis I, pairing of homologous chromosomes occurs, resulting in the exchange of chromatids. Subsequently, homologous chromosomes separate between each other resulting in a decrease in the number of chromosomes. In meiosis II it occurs that the sister chromatids separate, each of the chromosomes formed by separating two different cells. Down syndrome occurs when in the process of abnormal cell division it helps with added genetic material on chromosome 21. On the other hand, poly x syndrome is a genetic disorder that occurs in women, leading to the formation of three X chromosomes. instead of two only two chromosomes.

luisvaschetto luisvaschetto · Answer 2 · 2021-11-19T12:28:57+01:00

Trisomies are caused by faulty segregation during Meiosis I or Meiosis II. This process is known as non-disjunction.

A trisomy is an abnormal chromosomal condition characterized by the presence of an additional chromosome.

Trisomies are generally caused by the faulty separation of homologous chromosomes during meiosis I (i.e., Anaphase I).

Trisomies may also be caused by the non-disjunction of sister chromatids during Anaphase II.

In conclusion, trisomies are caused by faulty segregation during Meiosis I or Meiosis II. This process is known as non-disjunction.

Learn more in:

https://brainly.com/question/484286