Submitted to: Encyclopedia of Genetics
Publication Type: Book / Chapter
Publication Acceptance Date: January 7, 2012
Publication Date: N/A
Repetitive sequences, or repeats, account for a substantial portion of the eukaryotic genomes. These sequences include very different types of DNA with respect to mode of origin, function, structure, and genomic distribution. Two large families of repetitive sequences can be readily recognized, tandem repeats and dispersed repeats. High frequency and abundance as well as evolutionary conservation of repetitive sequences suggest that they serve important biological functions and should not be considered “junk DNA”. Current evidence indicates these sequences may play critical roles in evolution and human diseases. Several diseases, many of which are neurological, are associated with mutations and expansions to repeated sequences, including Huntington’s disease and Fragile X syndrome. Furthermore, repeated sequences are conserved between generations, a trait that could prove useful in identifying biomarkers for improving diagnostics and treatments for disease in the future.