Organization of repetitive DNA elements between genes

    Protein-coding genes comprise both expressed exons (dark green) and intervening introns (light grey regions). Repetitive DNA elements may be interspersed both within and between genes.  The latter include short or long interspersed elements (SINEs and LINEs), and regions with variable numbers of tandem repeats (VNTRs: micro- & minisatellites).

    Other repetitive elements found between coding genes include centromeric heterochromatin, which are genetically inert regions near the chromosomal centromeres that serve as an attachment point for microspindles during mitosis and meiosis, and Nucleolus-Organizing Regions (NORs), which comprise tandem repeats of rDNA genes on particular chromosomes. Centromeres and NORs are frequently detectable cytologically.

Figure ©2002 by Griffiths et al.; all text material © 2014 by Steven M. Carr