chromatid

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Related to Chromatids: Sister chromatids

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 ?
sister chromatids carrying the recessive allele to be transmitted to the
For instance, the sister chromatids do not separate at the anaphase stage of mitosis in the case of mutants that fail to undergo cleavage of cohesion (Hodges et al.
As cell division begins again, an apparatus called the spindle forms within each cell and gently pulls the sister chromatids apart, just as the maternal and paternal pairs are separated for the first division.
No distinction was made between types of somatic mutations, because detected chromosomal abnormalities were almost entirely breaks of chromosomes or of individual chromatids (Fig.
2008) found no hyperploidy/polyploidy in oocytes/zygotes (but reported increased metaphase II oocytes with prematurely separated chromatids after chronic BPA exposure).
Cohesin would be associated with sister chromatids.
In pre-reductional meiosis, which is the more common type, homologous chromosomes segregate in the first round of meiosis, and sister chromatids segregate in the second.
1] cells contained chromosomes with both sister chromatids stained uniformly dark.
Because the kinetochores are directly responsible for segregating chromatids during mitosis, a tempting hypothesis is that the asymmetric segregation is involved in nonrandom segregation of sister chromatids to daughter cells immediately after meiosis.
These markers include breaks in chromosomes or chromatids (DNA double-strands), abnormal recombination of DNA in cells of the immune system, and the formation of micronucleated reticulocytes (abnormal young red blood cells).