The definition is, a sister chromatid refers to the identical copies (chromatids) formed by the DNA replication of a chromosome, with both copies joined together by a common centromere. In other words, a sister chromatid may also be said to be 'one-half' of the duplicated chromosome. A pair of sister chromatids is called a dyad.
Biologists assigned universally accepted names to organisms because t<span>hey needed to create a unique name that would be recognized as belonging to one organism.</span>
