Repetitive DNA Elements
Role Of Repetitive Dna In Evolution And Impact On The Human Genome
Most eukaryotic genomes contain repetitive DNA. Although most repeated sequences have no known function, their impact and importance on genomes is evident. Mobile repeated elements have been a critical factor in gene evolution. It has been suggested that some types of repeats may be linked to speciation, since during the evolutionary period when there was a high activity of mobile elements, radiation of different species occurred.
There are several diseases linked to—or caused by—repetitive elements. Expansion of triplet repeats has been tied to fragile X syndrome (a common cause of mental retardation), Huntington's disease, myotonic muscular dystrophy, and several other diseases. In addition, the discovery of STR instability in certain cancers suggests that sequence instability may play a role in cancer progression.
Mobile elements have caused diseases when a new mobile element disrupts an important gene. Neurofibromatosis type 1, for example, is caused by the insertion of an Alu element in the gene NF1. Alternatively, recombination between two repeated elements within a gene will alter its function, also causing disease. Many examples of cancers (e.g., acute myelogenous leukemia) and inherited diseases (e.g., alpha thalassemia) are caused by mobile-element-based recombinations.
- Repetitive DNA Elements - Application Of Repeats To Human Genomic Studies
- Repetitive DNA Elements - Transposable Elements
- Other Free Encyclopedias
Medicine EncyclopediaGenetics in Medicine - Part 4Repetitive DNA Elements - Types Of Repetitive Elements, Tandem Arrays, Transposable Elements, Role Of Repetitive Dna In Evolution And Impact On The Human Genome