Centromere

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centromere

[′sen·trə‚mir]
(cell and molecular biology)
A specialized chromomere to which the spindle fibers are attached during mitosis. Also known as kinetochore; kinomere; primary constriction.

Centromere

 

a part of a chromosome that plays a fundamental role in its movement during cell division (mitosis). In the metaphase stage of mitosis, the area of the centromere within the chromosome is less dense than the chromosome’s other areas and forms a primary constriction that divides the chromosome into two sections; the position of this constriction is a basis for the classification of chromosomes. The cytoplasmic filaments (microtubules) of the spindle of cell division are attached to the centromere by their ends.

Some organisms, such as members of the genus Luzula and the scorpion, have polycentromeric chromosomes with a diffuse centromere and with the spindle filaments attached to the chromosome along its entire length. With a light microscope a cluster of chromomeres may be seen near the centromere of a chromosome during metaphase. Examination of mammalian cells with an electron microscope reveals a three-layered structure near each of the two longitudinal chromosome filaments, or chromatids. This structure is a kinetochore plate, whose interaction with the spindle filaments results in the even distribution of chromosomes among the daughter cells during cell division. Chromosomal aberrations involving the chromomere hamper the distribution of chromosomal material during mitosis and meiosis and alter the organism’s karyotype. Chromosomes that lack a centromere cannot take part in mitosis.

I. I. KIKNADZE

References in periodicals archive ?
Phosphoserines on maize CENTROMERIC HISTONE H3 and histone H3 demarcate the centromere and pericentromere during chromosome segregation.
New York University researchers focused on the organization and functioning of the centromere, which is responsible for chromosome segregation--a process that ensures that replicating cells receive a complete copy of the genome.
The former shows reactions to nucleolar RNA and RNA polymerase I, and the latter reacts to centromere (Table 1).
The functional but evolutionarily immature centromere in the horse may provide a model to study factors responsible for how centromeres function.
Mutational and in vitro protein-binding studies on centromere DNA from Saccharomyces cerevisiae.
The CENP-A deposition machinery is recruited to centromeres in a cell cycle-regulated manner by inner kinetochore proteins associated with CENP-A, most notably CENP-C.
Recall that only about 1 % of the human genome codes for expressed proteins; the other 99% is made up of things such as introns, chromatin structural regions, life centromeres and telomeres, non-protein coding expressed RNAs, and a lot of other sequence material whose utility we don't much know about.
A hypothesis that holocentric chromosomes represent a primitive character is supported by contention that the localized centromeres are more specialized structures than diffuse centromeres and process of fragmentation increases the chromosome number resulting in greater variability and better adaptation capability.
He hopes to use information about centromeres to create "artificial chromosomes" that can be used to introduce new genetic traits into crop plants.
At least 100 well-spread metaphases with 46 [+ or -] 1 centromeres were examined (Bavorova et al.
They've even decoded some of the gene-poor chromosomal regions called centromeres.
the company's co-founder, to extend technology for rapidly identifying centromeres in a wide range of plants.