Chromatid

Diagram of a duplicated and condensed metaphase eukaryotic chromosome.
(1) Chromatid – one of the two parts of the chromosome after duplication.
(2) Centromere – the point where the two chromatids touch.
(3) Short arm. (4) Long arm.

Chromatids are the daughter strands of a duplicated chromosome which are joined by a single centromere. When the centromere divides, the chromatids become separate chromosomes.

Each of the two daughter chromatids contains the same DNA and chromatin protein as its original chromosome. But in meiosis, crossing over (exchanges) take place between two of the non-sister chromatids. This has profound consequences: it produces genetic recombination, and increases the variability of gametes.

Reference

Part of this article consists of modified text from Wikipedia, and the article is therefore licensed under GFDL.