What is aneuploidy caused by?

Aneuploidy:

1. This is a type of chromosomal abnormality that is caused due to abnormal chromosome numbers in cells.
2. The abnormal chromosome number is due to various forms of mutations as well as improper segregation of chromosomes during cell division.

Cause of aneuploidy:

1. One of the most common causes of aneuploidy is the nondisjunction of chromosomes ( the failure of chromosomes to separate normally during meiosis).
2. The nondisjunction can occur during meiosis I and meiosis II or mitosis, but the most common non-disjunction during meiosis I.
3. After nondisjunction, in maternal chromosomes during meiosis I the resulting gamete either lacks the chromosome or contains 2 copies of one chromosome so the resulting zygote after fusion of gametes will be trisomic or monosomic.
4. Another cause includes mutations that may lead to the deletion or insertion of chromosomes into a nucleus.