sisterchromosome

A sister chromosome refers to one of a pair of identical chromosomes that are replicated during the S phase of the cell cycle and are joined together at a common area called the centromere. This pairing occurs during the process of DNA replication, resulting in two identical copies called sister chromatids. These sister chromatids are considered part of the same chromosome until they are separated during cell division.

During mitosis and meiosis, sister chromatids play a crucial role in ensuring accurate distribution of genetic material to daughter cells. In mitosis, the sister chromatids are separated and pulled to opposite poles of the cell, ensuring each daughter cell inherits an identical set of chromosomes. In meiosis, homologous chromosomes pair up initially, and sister chromatids are separated during the second meiotic division to produce gametes with half the chromosome number.

The cohesion of sister chromatids is maintained by protein complexes called cohesins, which hold them together until the proper phase of cell division. The accurate segregation of sister chromatids is essential for genetic stability and preventing chromosomal abnormalities, such as aneuploidy.

In summary, sister chromosomes or chromatids are identical copies formed from a single chromosome during DNA replication, playing a vital role in the process of cell division and genetic inheritance.