Acentric fragment

Acentric fragment

An acentric fragment is a segment of a chromosome that lacks a centromere.

Because it is the centromere is the point of attachment for the mitotic apparatus, such fragments are not evenly distributed to the daughter cells in cell division (mitosis and meiosis). As a result one of the daughters will lack the acentric fragment.

Lack of the acentric fragment in one of the daughter cells may have deleterious or consequences, depending on the function of the DNA in this region of the chromosome. In the case of a haploid organism or a gamete, it will be fatal if essential DNA is contained in that DNA segment. In the case of a diploid organism, the daughter cell lacking the acetric fragment will show expression of any recessive genes found in the homologous chromosome. Developmental geneticists look to cells and cell lineages lacking unpaired chromosome segments produced this way as a means of identifying essential genes for specific functions.

Acentric fragments are commonly generated by chromosome-breaking events, such as irradiation. Acentric fragments can also be produced when an inverted segment is present in one member of a chromosome pair. In that case, a crossover event will result in one chromosome with two centromeres and an acentric fragment. The acentric fragment will be lost as explained above, and chromosomes with two centromeres will break unevenly during mitosis, resulting in one daughter lacking essential genes.


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  • acentric fragment — acentric fragment. См. ацентрический фрагмент. (Источник: «Англо русский толковый словарь генетических терминов». Арефьев В.А., Лисовенко Л.А., Москва: Изд во ВНИРО, 1995 г.) …   Молекулярная биология и генетика. Толковый словарь.

  • acentric fragment — acentrinis fragmentas statusas T sritis augalininkystė apibrėžtis Chromosomos ar chromatidės dalis, neturinti centromeros. atitikmenys: angl. acentric fragment rus. ацентрический фрагмент …   Žemės ūkio augalų selekcijos ir sėklininkystės terminų žodynas

  • acentric — Lacking a center; in cytogenetics, denoting a chromosome fragment without a centromere. [G. a priv. + kentron, center] * * * acen·tric ( )ā sen trik adj lacking a centromere <acentric chromosomes> * * * n. (in …   Medical dictionary

  • fragment — A small part broken from a larger entity. acentric f. SYN: acentric chromosome. Brimacombe f. a ribonucleoprotein f. obtained by mild ribonuclease treatment of ribosomes. butterfly f. a broad triangular f. that is commonly present in …   Medical dictionary

  • acentric — n. (in genetics) a chromosome or fragment of a chromosome that has no centromere. Since acentrics cannot attach to the spindle they are usually lost during cell division. They are often found in cells damaged by radiation. Derivatives: acentric… …   The new mediacal dictionary

  • acentric — adjective 1. lacking a centromere an acentric chromosome fragment • Pertains to noun: ↑centromere 2. not centered or having no center • Similar to: ↑eccentric, ↑nonconcentric …   Useful english dictionary

  • acentric — adj. [Gr. a, without; kentrol, center] Pertaining to not being centered; lacking a centromere when referring to a chromosome or chromosome fragment …   Dictionary of invertebrate zoology

  • Acentric chromosome — A fragment of a chromosome (one of the microscopically visible carriers of the genetic material DNA) that is lacking a centromere (the “waist” of the chromosome essential for the division and the retention of the chromosome in the cell) and so is …   Medical dictionary

  • acentric chromosome — Chromosome fragment lacking a centromere …   Glossary of Biotechnology

  • Chromosome, acentric — A fragment of a chromosome (one of the microscopically visible carriers of the genetic material DNA) that is lacking a centromere (the “waist” of the chromosome essential for the division and the retention of the chromosome in the cell) and so is …   Medical dictionary

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