chromatid


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Related to chromatid: chromomere

chromatid

(krō`mətəd): see chromosomechromosome
, structural carrier of hereditary characteristics, found in the nucleus of every cell and so named for its readiness to absorb dyes. The term chromosome
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; crossing overcrossing over,
process in genetics by which the two chromosomes of a homologous pair exchange equal segments with each other. Crossing over occurs in the first division of meiosis. At that stage each chromosome has replicated into two strands called sister chromatids.
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.

Chromatid

 

one of the components of a chromosome, formed in the nucleus during the interphase of the cell nucleus as a result of the chromosome’s duplication. In mitosis, each chromosome consists of two chromatids; after separating into the daughter nuclei, each chromatid becomes an independent chromosome. In meiosis, homologous chromosomes come together in pairs to make up a four-chromatid structure, or tetrad.

According to the single-chain chromosome model, each chromatid contains in cross section a single tightly coiled and condensed double-strand molecule of deoxyribonucleic acid (DNA). In the multichain chromosome model, it is assumed that each chromatid contains in cross section several DNA molecules, in which case various types of chromatids are distinguished, such as semichromatids and quarter-chromatids. Most experiments have confirmed the single-chain model.

I. I. KIKNADZE

chromatid

[′krō·mə·təd]
(cell and molecular biology)
One of the pair of strands formed by longitudinal splitting of a chromosome which are joined by a single centromere in somatic cells during mitosis.
One of a tetrad of strands formed by longitudinal splitting of paired chromosomes during diplotene of meiosis.
References in periodicals archive ?
With either type of chromatid segregation, all combinations of
The alteration of sister chromatid exchange frequencies in Behcet's disease with and without HLA-B51.
Sharma, Sister chromatid exchange andchromosome aberrations induced by curcumine and Tartrazine on on mammalian cells in vivo.
Dynamic mosaicism occurs as a consequence of sister chromatid exchange (SCE) of the ring chromosome during replication, resulting in several unbalanced chromosome outcomes.
Effect of sodium azide on sister chromatid exchanges in human lymphocytes and Chinese hamster ovary cells.
3-fold increase in the mean number of sister chromatid exchanges (the number of crossover events in a chromosome pair), from 6.
For example, Schantz et al demonstrated that sensitivity to chromatid breaks of lymphocytes treated with bleomycin was one such marker.
Chromosome aberrations, sister chromatid exchange and micronuclei formation analysis in mice after in vivo exposure to bacoside A and B.
Teniposide also caused a dose-related increase in sister chromatid exchanges in Chinese hamster ovary cells and it has been shown to be embryotoxic and teratogenic in rats receiving teniposide during organogenesis.
The acentric chromatid poleward movement is mediated through DNA tethers that connect the acentric fragment to its centric partner.
Genotoxic effects observed in welders include elevated 8-hydroxydeoxyguanine in urine; DNA-protein crosslinks, sister chromatid exchanges, and increased micronuclei in lymphocytes; increased DNA strand breaks, chromosome aberrations, and increased micronuclei in buccal epithelial cells (Antonini et al.