Anaphase is a stage in cell division where two sister copies of DNA called chromatids break apart, and their respective chromosomes migrate to the ends of the cell. This occurs in all eukaryotic cells, or those belonging to complex multicellular organisms, during cell division processes called mitosis and meiosis. In mitosis, the end result is two identical copies of a parent cell. Meiosis creates four cells with a mixture of genetic material, each containing half the chromosomes needed to make an adult organism.
Cell division is a five stage process. It starts with interphase, moves into prophase, and is followed by metaphase to prepare for anaphase, ending in telophase. At each step, the cell performs certain actions to facilitate the duplication of genetic material and the generation of daughter cells. The stages before anaphase duplicate the chromosomes in the cell to create a set of chromatids. They also allow the cell to develop a spindle, a structure that works during cell division to separate the chromatids and pull the resulting chromosomes to either end of the cell.
The first step of anaphase involves the deployment of proteins to cleave the chromatids. Errors during this process can result in problems with the resulting chromosomes, as they may acquire extra genetic material or could have missing pieces. In the next step, the chromosomes are pulled to either end of the cell, preparing for the part of the process where the cell breaks into two copies. A phenomenon called anaphase lag can create errors if a chromosome fails to migrate; one daughter cell will have too many chromosomes, and other will have too few.
In successful mitosis, anaphase allows the cell to create two identical copies. Each will contain the same chromosomes, and can perform the same functions as the parent cell. Meiosis involves the mixture of genetic material to create a grab bag of genes on each chromosome. The paired daughter cells divide again to create a set of four cells with complementary DNA. These haploid cells, known as gametes, can combine with similar cells from another organism to create an embryo.
Mistakes can happen during anaphase or any of the other phases of cell division. The body may be able to identify cells with DNA replication mistakes and can tag them for destruction to prevent their duplication and perpetuation. Sometimes it does not identify these issues. When it fails, people can develop neoplasms, where uncontrolled cell growth occurs because of a genetic mistake. In the case of gametes, errors may result in the development of birth defects or the creation of a carrier who could have children with genetic diseases.
By Mary McMahon
Ever since she began contributing to the site several years ago, Mary has embraced the exciting challenge of being a All The Science researcher and writer. Mary has a liberal arts degree from Goddard College and spends her free time reading, cooking, and exploring the great outdoors.