what are sister chromatids

Sister chromatids are two identical copies of the same chromosome formed by DNA replication, attached to each other by a structure called the centromere. During cell division, they are separated from each other, and each daughter cell receives one copy of the chromosome. A pair of sister chromatids is called a dyad, and a full set of sister chromatids is created during the synthesis (S) phase of interphase, when all the chromosomes in a cell are replicated. Sister chromatids are by and large identical since they carry the same alleles, also called variants or versions, of genes because they derive from one original chromosome. Sister chromatids play an important role in maintaining the integrity of the genome by being involved in DNA repair. They are usually spatially close to each other, compared to the homologous chromosomes. Non-sister chromatids come from homologous chromosomes, and they code for the same genes, but are not genetically identical. Occasionally, genetic material is exchanged between non-sister chromatids during meiosis, allowing for new arrangements of genes to be passed to the progeny.