Centromere

The cinched "waist" of the chromosome essential for the division and the retention of the chromosome in the cell. The centromere is a uniquely specialized region of the chromosome to which spindle fibers attach during cell division. The human centromere contains a 3-million-base stretch of DNA embedded in what has been called the centromere and that is all it takes to make a functional centromere. The nature of this core DNA indicates that, rather than being highly conserved, the centromere has changed significantly during primate evolution.

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1. The nonstaining primary constriction of a chromosome which is the point of attachment of the spindle fiber; provides the mechanism of chromosome movement during cell division; the c. divides the chromosome into two arms, and its position is constant for a specific chromosome : near one end (acrocentric), near the center (metacentric), or between (submetacentric). [centro- + G. meros, part]

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cen·tro·mere 'sen-trə-.mi(ə)r n the point or region on a chromosome to which the spindle attaches during mitosis and meiosis called also kinetochore

cen·tro·mer·ic .sen-trə-'mi(ə)r-ik, -'mer- adj

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(kinetochore)

n.

the part of a chromosome that joins the two chromatid to each other and becomes attached to the spindle during mitosis and meiosis. When chromosome division takes place the centromeres split longitudinally.

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cen·tro·mere (senґtro-mēr) [centro- + -mere] the region of the chromosome at which the sister chromatids are joined and by which the chromosome is attached to the spindle during cell division; it is required for normal segregation in mitosis and meiosis. According to its location, a centromere is said to be metacentric (central), submetacentric (off center), acrocentric (near one end), or telocentric (at one end). The last type does not occur in human chromosomes. centromeric adj

Position of the centromere in (A) metacentric; (B) submetacentric; (C) acrocentric; and (D) telocentric chromosomes.