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chromatid (n.)
1.one of two identical strands into which a chromosome splits during mitosis
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⇨ definição - Wikipedia
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chromatid (n.)
fibril, fibrilla, filament, strand[Hyper.]
chromosome[Desc]
Wikipedia
A chromatid is one of the two copies of DNA making up a duplicated chromosome, which are joined at their centromeres, for the process of cell division (mitosis or meiosis). They are normally identical ("homozygous") but may have slight differences in the case of mutations, in which case they are heterozygous. They are called sister chromatids so long as they are joined by the centromeres. When they separate (during anaphase of mitosis and anaphase 2 of meiosis), the strands are called daughter chromosomes (although having the same genetic mass as the individual chromatids that made up its parent, the daughter "molecules" are still referred to as chromosomes much as one child is not referred to as a single twin). [1]
In other words, a chromatid is "one-half of two [normally] identical copies of a replicated chromosome".[2] The two copies may have slight differences due to mutations. A chromatid is simply a copied chromosome which is paired with a (normally) identical chromosome at the centromere. It should not be confused with the ploidy of an organism, which is the number of homologous versions of a chromosome.
A bivalent is a pair of sister chromatids. This occurs in prophase I of meiosis. After DNA replication, the two sister chromatids align side-by-side and appear to have an undivided centromere, in contrast to mitosis, in which each chromatid appears to have its own separate centromere.
The term bivalent can also be used to describe protein morphology.[3]
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