Inversion, paracentric chromosome
A basic type of chromosome rearrangement in which a segment that does not include the centromere (and so is paracentric) has been snipped out of a chromosome, turned through 180 degrees (inverted), and inserted right back into its original location in chromosome. The feature that makes it paracentric is that both breaks are on the same side of the centromere so that the centromere (the point at which the chromosome attaches to the spindle) is not affected. Any chromosome inversion can be inherited and have come from one of the parents to a child. Or the inversion can appear for the first time in a child. An inversion can be "balanced", meaning that it has all the genes present in the normal uninverted chromosome. Or an inversion can be "unbalanced", meaning that genes been have deleted (lost) or duplicated. A balanced inversion in a child causes no problems. An unbalanced inversion is abnormal and is often associated with problems such as development delay (and later, mental retardation) and multiple congenital anomalies (birth defects). Inversions can also be acquired in a body cell (a somatic cell) and be a step involving that cell in a precancerous and cancerous process.

Medical dictionary. 2011.

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  • Chromosome inversion, paracentric — A basic type of chromosome rearrangement. A segment that does not include the centromere (and so is paracentric) has been snipped out of a chromosome, turned through 180 degrees (inverted), and inserted right back into its original location in… …   Medical dictionary

  • Paracentric chromosome inversion — A basic type of chromosome rearrangement. A segment that does not include the centromere (and so is paracentric) has been snipped out of a chromosome, turned through 180 degrees (inverted), and inserted right back into its original location in… …   Medical dictionary

  • paracentric inversion — inversion in which the inverted chromosome segment is on one side of the centromere, i.e., both breaks occur in one arm. See illustration at aberration …   Medical dictionary

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  • inversion — n. 1) the turning inwards or inside out of a part or organ: commonly applied to the state of the uterus after childbirth when its upper part is pulled through the cervical canal. 2) a chromosome mutation in which a block of genes within a… …   The new mediacal dictionary

  • paracentric — I. |parə|sen.trik adjective Etymology: para (I) + centric 1. : being a type of key and keyway used with pin tumbler cylinder locks and having longitudinal ribs and grooves projecting beyond the center to hinder picking 2. : being an inversion… …   Useful english dictionary

  • paracentric — para·cen·tric sen trik adj being an inversion that occurs in a single arm of one chromosome and does not involve the chromomere compare PERICENTRIC …   Medical dictionary

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  • Chromosomal inversion — A clay model showing why heterozygous inversion loops are visible in polytene chromosome preparations …   Wikipedia

  • heredity — /heuh red i tee/, n., pl. heredities. Biol. 1. the transmission of genetic characters from parents to offspring: it is dependent upon the segregation and recombination of genes during meiosis and fertilization and results in the genesis of a new… …   Universalium

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