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The term "repeated sequence" was first used by Roy John Britten and D. E. Kohne in 1968; they found out that more than half of the eukaryotic genomes were repetitive DNA through their experiments on reassociation of DNA. [5] Although the repetitive DNA sequences were conserved and ubiquitous, their biological role was yet unknown.
Since a sequence of single-stranded DNA needs to find its complementary strand to reform a double helix, common sequences renature more rapidly than rare sequences. Indeed, the rate at which a sequence will reassociate is proportional to the number of copies of that sequence in the DNA sample. A sample with a highly-repetitive sequence will ...
A tract of repetitive DNA in which a motif of a few base pairs is tandemly repeated numerous times (e.g. 5 to 50 times) is referred to as microsatellite DNA. Thus direct repeat tandem sequences are a form of microsattelite DNA. The process of DNA mismatch repair plays a prominent role in the formation of direct trinucleotide repeat expansions. [2]
These repeated DNA sequences often range from a pair of nucleotides to a whole gene, while the proximity of the repeat sequences varies between widely dispersed and simple tandem arrays. [3] The short tandem repeat sequences may exist as just a few copies in a small region to thousands of copies dispersed all over the genome of most eukaryotes. [4]
All tandem repeat arrays are classifiable as satellite DNA, a name originating from the fact that tandem DNA repeats, by nature of repeating the same nucleotide sequences repeatedly, have a unique ratio of the two possible nucleotide base pair combinations, conferring them a specific mass density that allows them to be separated from the rest of the genome with density-based laboratory ...
Many LCRs are concentrated in "hotspots", such as the 17p11-12 region, 27% of which is composed of LCR sequence. NAHR and non-homologous end joining (NHEJ) within this region are responsible for a wide range of disorders, including Charcot–Marie–Tooth syndrome type 1A , [ 5 ] hereditary neuropathy with liability to pressure palsies , [ 5 ...
Minisatellites are a type of DNA tandem repeat sequence, meaning that the sequences repeat one after another without other sequences or nucleotides in between them. Minisatellites are characterized by a repeat sequence of about ten to one hundred nucleotides, and the number of times the sequence repeats varies from about five to fifty times.
Copy number variation was initially thought to occupy an extremely small and negligible portion of the genome through cytogenetic observations. [12] Copy number variations were generally associated only with small tandem repeats or specific genetic disorders, [13] therefore, copy number variations were initially only examined in terms of specific loci.