the sister chromatids become separated during
During cell division, the identical copies (called a  sister chromatid pair ) are joined at the region called the centromere (2). Once the paired sister chromatids have separated from one another (in the anaphase of mitosis) each is known as a daughter chromosome.The short arm of the left chromatid (3), and the long arm of the right chromatid (4), are also marked.A chromatid (Greek khrÅmat- 'color' + -id) is one copy of a newly replicated chromosome, which typically is joined to the other copy by a single centromere.Before replication, one chromosome is composed of one DNA (double-helix) molecule.he short arm of the left chromatid (3), and the long arm of the right chromatid (4), are also marked. A chromatid (Greek khrÅmat- 'color' + -id) is one copy of a newly replicated chromosome, which typically is joined to the other copy by a single centromere.