<Table> <Tr> <Td> </Td> <Td> This article needs additional citations for verification . Please help improve this article by adding citations to reliable sources . Unsourced material may be challenged and removed . (April 2018) (Learn how and when to remove this template message) </Td> </Tr> </Table> <Tr> <Td> </Td> <Td> This article needs additional citations for verification . Please help improve this article by adding citations to reliable sources . Unsourced material may be challenged and removed . (April 2018) (Learn how and when to remove this template message) </Td> </Tr> <P> A chromatid (Greek khrōmat -' color' + - id) is one copy of a newly copied chromosome which is still joined to the original chromosome by a single centromere . </P> <P> Before replication, one chromosome is composed of one DNA molecule . Following replication, each chromosome is composed of two DNA molecules; in other words, DNA replication itself increases the amount of DNA but does not increase the number of chromosomes . The two identical copies--each forming one half of the replicated chromosome--are called chromatids . During the later stages of cell division these chromatids separate longitudinally to become individual chromosomes . </P>

One of two identical sister parts of a copied chromosome is called a chromatid