A minisatellite is a section of DNA that consists of a short series of bases 10-100bp, these occur at more than 1000 locations in the Genome. This series usually contains the same central sequence of letters “GGGCAGGAXG” (where X can be any letter). This sequence encourages chromosomes to swap DNA, When this happens frequent mistakes are made, this causes minisatellites at over 1000 locations in a persons genome to have slightly different numbers of repeats, thereby making them unique.
"Minisatellites" consist of repetitive, generally GC-rich, variant repeats that range in length from 10 to over 100 bp. These variant repeats are tandemly intermingled, which makes minisatellites ideal for studying DNA turnover mechanisms. In molecular biology, two nucleotides on opposite complementary DNA or RNA strands that are connected via hydrogen bonds are called a base pair (often abbreviated bp). ...
The general structure of a section of DNA Deoxyribonucleic acid (DNA) is a nucleic acid that contains the genetic instructions for the biological development of a cellular form of life or a virus. ...
Since the fortuitous discovery of the first human minisatellite in 1980 by A.R. Wyman and R. White and especially the discovery that the extreme polymorphism of minisatellites made them superb for DNA fingerprinting by Alec Jeffreys, this class of repeats has been an intense focus of studies that have addressed the turnover mechanisms that provoke their instability. Due to their high level of polymorphism, minisatellites have been extensively used for DNA fingerprinting as well as for genetic markers in linkage analysis and population studies. Genetic fingerprinting or DNA testing is a technique to distinguish between individuals of the same species using only samples of their DNA. Its invention by Sir Alec Jeffreys at the University of Leicester was announced in 1985. ...
Professor Sir Alec John Jeffreys, FRS, (born in 9 January 1950 at Luton in Bedfordshire) is a British geneticist, who developed techniques for DNA fingerprinting and DNA profiling. ...
In biology, polymorphism can be defined as the occurrence in the same habitat of two or more forms of a trait in such frequencies that the rarer cannot be maintained by recurrent mutation alone. ...
A genetic marker is a known DNA sequences (e. ...
Genetic linkage occurs when particular alleles are inherited together. ...
Minisatellites have also been implicated as regulators of gene expression (e.g., at levels of transcription, alternative splicing, or imprint control) or as part of bona fide open reading frames. Gene expression, or simply expression, is the process by which a genes DNA sequence is converted into the structures and functions of a cell. ...
Transcription is the process through which a DNA sequence is enzymatically copied by an RNA polymerase to produce a complementary RNA. Or, in other words, the transfer of genetic information from DNA into RNA. In the case of protein-encoding DNA, transcription is the beginning of the process that ultimately...
Various modes of alternative splicing Alternative splicing is the process that occurs in eukaryotes in which the splicing process of a pre-mRNA transcribed from one gene can lead to different mature mRNA molecules and therefore to different proteins. ...
An open reading frame or ORF is any sequence of DNA or RNA that can be translated into a protein. ...
Finally, minisatellites have been associated with chromosome fragile sites and are proximal to a number of recurrent translocation breakpoints. Figure 1: A representation of a condensed eukaryotic chromosome, as seen during cell division. ...
Some human minisatellites (~10%) have been demonstrated to be hypermutable, with an average mutation rate in the germline higher that 0.5% up to over 20%, making them the most unstable region in the human genome known to date. It is interesting to note that while other genomes (mouse, rat and pig) contain minisatellite-like sequences, none was found to be hypermutable. Since all hypermutable minisatellites contain internal variants, they provide extremely informative systems for analyzing the complex turnover processes that occur at this class of tandem repeat. Minisatellite variant repeat mapping by PCR (MVR-PCR) has been extensively used to chart the interspersion patterns of variant repeats along the array, which provides details on the structure of the alleles before and after mutation. The human genome is the genome of Homo sapiens. ...
Studies have revealed distinct mutation processes operating in somatic and germline cells. Somatic instability detected in blood DNA shows simple and rare intra-allelic events two to three orders of magnitude lower than in sperm. In contrast, complex inter-allelic conversion-like events occur in the germline.
Additional analyses of DNA sequences flanking human minisatellites have also revealed an intense and highly localized meiotic crossover hotspot that is centered upstream of the unstable side of minisatellite arrays. Repeat turnover therefore appears to be controlled by recombinational activity in DNA that flanks the repeat array and results in a polarity of mutation. These findings have suggested that minisatellites most probably evolved as bystanders of localized meiotic recombination hotspots in the human genome. Recombination hotspots are sites in the genome of sexually reproducing organisms that exhibit elevated rates of meiotic recombination. ...
Finally, studies have shown that the evolutionary fate of minisatellites tends towards an equilibrium distribution in the size of alleles, until mutations in the flanking DNA affect the recombinational activity of a minisatellite by suppressing DNA instability. Such event would ultimately lead to the extinction of a hypermutable minisatellite by meiotic drive.
In humans, 90% of minisatellites are found at the sub-telomeric region of chromosomes. The telomere sequence is a minisatellite repeat: TTAGGG TTAGGG TTAGGG ...
See also silly boy Fragile X Syndrome is the most common inherited cause of mental impairment, and the most common known cause of autism. ...
Microsatellites, or Simple Sequence Repeats (SSRs), are polymorphic loci present in nuclear DNA that consist of repeating units of 1-4 base pairs in length [1]. They are typically neutral, co-dominant and are used as molecular markers which have wide-ranging applications in the field of genetics, including kinship...
This is a term from genetics, which describes a pattern that helps determine an individuals inherited traits. ...
A telomere is a region of highly repetitive DNA at the end of a chromosome that functions as a disposable buffer. ...
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