A tandem repeat is a sequence of two or more DNA base pairs that is repeated in such a way that the repeats lie adjacent to each other on the chromosome. Tandem repeats are generally associated with non-coding DNA. In some instances, the number of times the DNA sequence is repeated is variable. Such variable tandem repeats are used in DNA fingerprinting procedures.
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Tandem repeat refers to a sequence phenomenon. What is a sequence? Really, you know the way the letters of our genome are arranged across on different chromosome. So for tandem repeats to occur, we have at least two or more of base pairs, and these base pairs are repeated in a way that they can, indeed, be unique to individuals or be more common in set populations than others. And because of this uniqueness, tandem repeats can indeed be used for fingerprinting... to remember that tandem repeats tend to occur in a part of the genome that doesn't code for protein, what we will refer to as non-coding regions.
Charles N. Rotimi, Ph.D.
Director, Center for Research on Genomics and Global Health; Senior Investigator, Inherited Disease Research Branch
Dr. Rotimi is the director of the Center for Research on Genomics and Global Health (CRGGH), whose mission is to advance research into the role of culture, lifestyle, genetics and genomics in health disparities. Dr. Rotimi develops genetic epidemiology models and conducts population genetics research that explores the patterns and determinants of common complex diseases in the African diaspora and other human populations. A key focus of Dr. Rotimi's research is understanding the triangular relationship between obesity, hypertension and diabetes, which together account for more than 80% of the health disparities between African Americans and European Americans.