Definition of Sister Chromatids

The sister chromatids are formed as a result of the process of DNA replication and they are actually the two identical copies of the same chromosome. They are attached with each other through a structure that is named as the centromere. When the cell undergoes the process of division (mitosis and meiosis II), these sister chromatids get separated from one another and hence the resulting daughter cells receive a copy of the chromosome.

The sister chromatids are also known to be the one-half of a duplicated chromosome. The chromosomes are replicated in the S phase of the interphase and hence the full set of sister chromatids is formed at this point.