What is the role of nondisjunction in chromosomal disorders?

Nondisjunction is a process that can lead to chromosomal disorders.

During cell division, chromosomes are supposed to separate evenly into two daughter cells. However, sometimes this process goes wrong, and one cell ends up with an extra chromosome while the other is missing one. This is called nondisjunction.

Nondisjunction can occur during either meiosis or mitosis. When it happens during meiosis, it can result in gametes (sperm or eggs) with an abnormal number of chromosomes. If one of these gametes is fertilized, the resulting zygote will also have an abnormal number of chromosomes. This can lead to conditions such as Down syndrome, Turner syndrome, or Klinefelter syndrome.

When nondisjunction occurs during mitosis, it can result in somatic cells (cells that make up the body) with an abnormal number of chromosomes. This can lead to conditions such as mosaic Down syndrome, where some cells have an extra chromosome 21 and others do not.

Overall, nondisjunction is a key factor in the development of chromosomal disorders. By disrupting the normal distribution of chromosomes during cell division, it can lead to conditions that affect a person's physical and intellectual development.