Question

Some people can have atypical karyotypes, which are caused by an error during one of the processes of cell division. Which process would an error result in an individual having either an extra or a missing chromosome?

A. Mitosis
B. Meiosis
C. Both
D. Neither

Answer 1

Answer c, both the processes of mitosis and meiosis can result in an individual having either an extra or a missing chromosome.

Errors during dividing of sex cells (meiosis):

During the meiosis process, the sex cells divide and create new sex cells with half the number of chromosomes. Sperm and eggs are sex cells. Normally, meiosis causes each parent to give 23 chromosomes to a pregnancy. When a sperm fertilizes an egg, the union leads to a baby with 46 chromosomes. During meiosis, if there is any abnormality it may lead to either trisomic condition (having extra chromosome) of monosomic condition (missing chromosome) and both the condition could lead to either syndromic child or loss in pregnancy.

Errors during dividing of other cells (mitosis):

During mitosis process, the dividing of all other cells in the body takes place. Mitosis causes the number of chromosomes to double to 92 and then split in half back to 46. It replaces skin cells, blood cells, and other types of cells that are damaged or naturally die. Any abnormality during mitosis could lead to the formation of cell with extra chromosomes (47 total) or have a missing chromosome (45 total).

The most common type of chromosomal abnormality is known as aneuploidy. Down, Turner and Klinefelter syndrome are some of the examples.