Final answer:
Aneuploidy is a condition where an organism has an abnormal number of chromosomes due to nondisjunction, leading to monosomy or trisomy. It can cause developmental and health issues, as seen in Down Syndrome, which is characterized by an extra copy of chromosome 21.
Step-by-step explanation:
Aneuploidy refers to the condition in which an organism has an abnormal number of chromosomes. This can occur due to nondisjunction during cell division, leading to gametes with too many or too few chromosomes. It includes conditions such as monosomy, where there is a loss of one chromosome, and trisomy, where there is a gain of an extra chromosome beyond the normal pair. The resulting genetic imbalance, such as gene dosage disturbances, can lead to developmental challenges and often impacts survival. A known example of aneuploidy is Down Syndrome, characterized by trisomy of chromosome 21.
Disorders of chromosome number, like aneuploidy, are commonly identified through a karyogram and are most often the result of nondisjunction, which can increase in likelihood with the age of the parents. This genetic alteration manifests in an array of physical and developmental symptoms that are characteristic of various chromosomal disorders. An individual with the correct number of chromosomes is termed euploid, which in humans equates to 22 pairs of autosomes and one pair of sex chromosomes. When this number is disrupted, we encounter the ramifications of aneuploidy on an organism's health and development.