Question

When homologous chromosomes don't separate in meiosis, it is called:

a) Aneuploidy
b) Non-disjunction
c) Crossing over
d) Independent assortment

Answer 1

The lack of separation of homologous chromosomes during meiosis is called nondisjunction, resulting in aneuploidy.

Step-by-step explanation:

When homologous chromosomes don't separate in meiosis, this is referred to as nondisjunction. Nondisjunction can occur during both phases of meiosis - Meiosis I, when homologous chromosomes fail to separate, and Meiosis II, when sister chromatids fail to separate. This improper segregation of chromosomes results in gametes that have an incorrect number of chromosomes, a condition known as aneuploidy. Thus, the correct option in this case would be b) Non-disjunction, which leads to the formation of gametes with an abnormal chromosome number, either n+1 (one extra chromosome) or n-1 (one fewer chromosome).