Explain how mistakes during meiosis or mitosis can produce a

Explain how mistakes during meiosis or mitosis can produce aneuploid cells (possibly from a particular disorder)

Solution

Answer:

Chromosomal alterations happen in both mitosis and meiosis. An extra or missing chromosome is a common cause of genetic disorders. Aneuploidy is the presence of an abnormal number of chromosomes in a cell. During the mitotic checkpoint, which generates identical daughter cells by arranging chromosomes into two equal groups, chromosomes are attached to string-like spindles and begin to move to the middle of the cell. Nondisjunction usually occurs as the result of a weakened mitotic checkpoint. If a checkpoint is weakened, the cell may fail to \'notice\' that a chromosome pair is not lined up on the mitotic plate. If chromosomes fail to attach to these spindles, a daughter cell will have either an extra or missing copy of a chromosome after the cell divides. One daughter cell would have a normal complement of chromosomes; the second would lack one. A third daughter cell may end up with the \'missing\' chromosome. One relatively common disorder caused by an extra chromosome is Down syndrome.