In Genetics, What Is a Chiasma?
A chiasma is a point of contact between sister chromatids that forms during meiosis, a process of cell division and replication used by a wide variety of organisms. At the chiasma, the chromatids can exchange genetic information, resulting in new combinations of genetic material. When the chromatids separate and become sister chromosomes, they will contain a different mix of genetic material than their parent chromosomes. This allows organisms to evolve genetically, creating new traits and passing them down to descendants. The chromatids are joined at the centromere, a point roughly in the middle of each chromatid. The formation of a chiasma occurs during meiosis I, the first phase in meiosis, when the paired chromosomes exchange genetic material before splitting into two cells, each containing half the genetic material of the original parent cell. Chiasmata play an important role in the process of replicating genetic material.
