What is the term for a condition in which an organism has extra sets of chromosomes?

The term for a condition in which an organism has extra sets of chromosomes is polyploidy. This condition occurs when an organism possesses more than two complete sets of chromosomes, which can happen through events such as errors in cell division during fertilization or development. Polyploidy is quite common in plants and can lead to significant variations in size, structure, and genetic expression.

The other terms involve different chromosomal abnormalities. Aneuploidy refers to the presence of an abnormal number of chromosomes, which is typically characterized by either an excess or a deficiency of specific chromosomes, rather than entire sets. Diploidy indicates the typical condition in most eukaryotic organisms where they possess two complete sets of chromosomes, one inherited from each parent. Monoploidy signifies the presence of only one complete set of chromosomes, which is typically observed in gametes (sperm and eggs). Understanding these distinctions helps clarify why polyploidy specifically refers to having extra sets of chromosomes.