Explain how a mistake in cellular division can cause Down sy

Explain how a mistake in cellular division can cause Down syndrome. In which cells of the body does this mistake occur?

Solution

Down syndrome is caused by an error in cell division called \"nondisjunction”. It is caused by a failure of the 21st chromosome to separate during egg or sperm development. This results in Trisomy of 21st chromosome, -three copies of chromosome 21 instead of the usual two.

This kind of Nondisjunction occurs during the development of gamete cells.

Karyotype of a Down syndrome individual will be = 47,XX,+21 for females and 47,XY,+21 for males.