The Chromatid reference article from the English Wikipedia on 24-Apr-2004
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Chromatid

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A chromatid forms one part of a chromosome after it has coalesced for the process of mitosis or meiosis. Each chromosome consists of two exactly identical ("sister") chromatids. After they have been pulled apart by the mitotic spindle, chromatids are called "chromosomes." Sister chromatids are joined at a point called the centromere.