Genetics, Nondisjunction

Excerpt

The human body is made up of trillions of somatic cells with the capacity to divide into identical daughter cells facilitating organismal growth, repair, and response to the changing environment. This process is called “mitosis.” In gamete production, a different form of cell division occurs called “meiosis.” The outcome of meiosis is the creation of four daughter cells, either sperm or egg cells, through reduction division which results in a haploid complement of chromosomes in each gamete. At fertilization, the haploid sperm cell nucleus merges with the haploid egg cell nucleus, which restores the diploid chromosomal complement and confirms the formation of the zygote. During anaphase of the cell cycle, chromosomes are separated to opposite ends of the cell to create two daughter cells. Nondisjunction is the failure of the chromosomes to separate, which produces daughter cells with abnormal numbers of chromosomes.