A report on DNA profiling

Sir Alec Jeffreys, pioneer of DNA profiling. His discovery led to the conviction of Colin Pitchfork in 1988.
Variations of VNTR allele lengths in 6 individuals.
Restriction Fragment Length Polymorphism
CBP chemist reads a DNA profile to determine the origin of a commodity.

Process of determining an individual's DNA characteristics.

- DNA profiling
Sir Alec Jeffreys, pioneer of DNA profiling. His discovery led to the conviction of Colin Pitchfork in 1988.

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Sir Alec Jeffreys, 2009

Alec Jeffreys

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Sir Alec Jeffreys, 2009
Alec Jeffreys

Sir Alec John Jeffreys, (born 9 January 1950) is a British geneticist known for developing techniques for genetic fingerprinting and DNA profiling which are now used worldwide in forensic science to assist police detective work and to resolve paternity and immigration disputes.

DNA strand slippage during replication of an STR locus. Boxes symbolize repetitive DNA units. Arrows indicate the direction in which a new DNA strand (white boxes) is being replicated from the template strand (black boxes). Three situations during DNA replication are depicted. (a) Replication of the STR locus has proceeded without a mutation. (b) Replication of the STR locus has led to a gain of one unit owing to a loop in the new strand; the aberrant loop is stabilized by flanking units complementary to the opposite strand. (c) Replication of the STR locus has led to a loss of one unit owing to a loop in the template strand. (Forster et al. 2015)

Microsatellite

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Tract of repetitive DNA in which certain DNA motifs are repeated, typically 5–50 times.

Tract of repetitive DNA in which certain DNA motifs are repeated, typically 5–50 times.

DNA strand slippage during replication of an STR locus. Boxes symbolize repetitive DNA units. Arrows indicate the direction in which a new DNA strand (white boxes) is being replicated from the template strand (black boxes). Three situations during DNA replication are depicted. (a) Replication of the STR locus has proceeded without a mutation. (b) Replication of the STR locus has led to a gain of one unit owing to a loop in the new strand; the aberrant loop is stabilized by flanking units complementary to the opposite strand. (c) Replication of the STR locus has led to a loss of one unit owing to a loop in the template strand. (Forster et al. 2015)
A partial human STR profile obtained using the Applied Biosystems Identifiler kit
Consensus neighbor-joining tree of 249 human populations and six chimpanzee populations. Created based on 246 microsatellite markers.
A number of DNA samples from specimens of Littorina plena amplified using polymerase chain reaction with primers targeting a variable simple sequence repeat (SSR, a.k.a. microsatellite) locus. Samples were run on a 5% polyacrylamide gel and visualized using silver staining.

Microsatellites are often referred to as short tandem repeats (STRs) by forensic geneticists and in genetic genealogy, or as simple sequence repeats (SSRs) by plant geneticists.

The structure of the DNA double helix. The atoms in the structure are colour-coded by element and the detailed structures of two base pairs are shown in the bottom right.

DNA

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Polymer composed of two polynucleotide chains that coil around each other to form a double helix carrying genetic instructions for the development, functioning, growth and reproduction of all known organisms and many viruses.

Polymer composed of two polynucleotide chains that coil around each other to form a double helix carrying genetic instructions for the development, functioning, growth and reproduction of all known organisms and many viruses.

The structure of the DNA double helix. The atoms in the structure are colour-coded by element and the detailed structures of two base pairs are shown in the bottom right.
Chemical structure of DNA; hydrogen bonds shown as dotted lines. Each end of the double helix has an exposed 5' phosphate on one strand and an exposed 3' hydroxyl group (—OH) on the other.
A section of DNA. The bases lie horizontally between the two spiraling strands ([[:File:DNA orbit animated.gif|animated version]]).
DNA major and minor grooves. The latter is a binding site for the Hoechst stain dye 33258.
From left to right, the structures of A, B and Z DNA
DNA quadruplex formed by telomere repeats. The looped conformation of the DNA backbone is very different from the typical DNA helix. The green spheres in the center represent potassium ions.
A covalent adduct between a metabolically activated form of benzo[a]pyrene, the major mutagen in tobacco smoke, and DNA
Location of eukaryote nuclear DNA within the chromosomes
T7 RNA polymerase (blue) producing an mRNA (green) from a DNA template (orange)
DNA replication: The double helix is unwound by a helicase and topo­iso­merase. Next, one DNA polymerase produces the leading strand copy. Another DNA polymerase binds to the lagging strand. This enzyme makes discontinuous segments (called Okazaki fragments) before DNA ligase joins them together.
Interaction of DNA (in orange) with histones (in blue). These proteins' basic amino acids bind to the acidic phosphate groups on DNA.
The lambda repressor helix-turn-helix transcription factor bound to its DNA target
The restriction enzyme EcoRV (green) in a complex with its substrate DNA
Recombination involves the breaking and rejoining of two chromosomes (M and F) to produce two rearranged chromosomes (C1 and C2).
The DNA structure at left (schematic shown) will self-assemble into the structure visualized by atomic force microscopy at right. DNA nanotechnology is the field that seeks to design nanoscale structures using the molecular recognition properties of DNA molecules.
Maclyn McCarty (left) shakes hands with Francis Crick and James Watson, co-originators of the double-helix model.
Pencil sketch of the DNA double helix by Francis Crick in 1953
A blue plaque outside The Eagle pub commemorating Crick and Watson
Impure DNA extracted from an orange

In technology, these sequence-specific nucleases are used in molecular cloning and DNA fingerprinting.

A strip of eight PCR tubes, each containing a 100 μL reaction mixture

Polymerase chain reaction

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Method widely used to rapidly make millions to billions of copies (complete or partial) of a specific DNA sample, allowing scientists to take a very small sample of DNA and amplify it (or a part of it) to a large enough amount to study in detail.

Method widely used to rapidly make millions to billions of copies (complete or partial) of a specific DNA sample, allowing scientists to take a very small sample of DNA and amplify it (or a part of it) to a large enough amount to study in detail.

A strip of eight PCR tubes, each containing a 100 μL reaction mixture
Placing a strip of eight PCR tubes into a thermal cycler
A thermal cycler for PCR
An older, three-temperature thermal cycler for PCR
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Ethidium bromide-stained PCR products after gel electrophoresis. Two sets of primers were used to amplify a target sequence from three different tissue samples. No amplification is present in sample #1; DNA bands in sample #2 and #3 indicate successful amplification of the target sequence. The gel also shows a positive control, and a DNA ladder containing DNA fragments of defined length for sizing the bands in the experimental PCRs.
Tucker PCR
Exponential amplification
Diagrammatic representation of an example primer pair. The use of primers in an in vitro assay to allow DNA synthesis was a major innovation that allowed the development of PCR.
"Baby Blue", a 1986 prototype machine for doing PCR

Applications of the technique include DNA cloning for sequencing, gene cloning and manipulation, gene mutagenesis; construction of DNA-based phylogenies, or functional analysis of genes; diagnosis and monitoring of genetic disorders; amplification of ancient DNA; analysis of genetic fingerprints for DNA profiling (for example, in forensic science and parentage testing); and detection of pathogens in nucleic acid tests for the diagnosis of infectious diseases.

Example of DNA profiling in order to determine the father of a child (Ch). Child's DNA sample should contain a mixture of different size DNA bands of both parents. In this case person #1 is likely the father

DNA paternity testing

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Example of DNA profiling in order to determine the father of a child (Ch). Child's DNA sample should contain a mixture of different size DNA bands of both parents. In this case person #1 is likely the father

DNA paternity testing is the use of DNA profiles to determine whether an individual is the biological parent of another individual.

Colin Pitchfork

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British double child-murderer and rapist.

British double child-murderer and rapist.

He was the first person convicted of rape and murder using DNA profiling after he murdered two girls in neighbouring Leicestershire villages, the first in Narborough, in November 1983, and the second in Enderby in July 1986.

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Variable number tandem repeat

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Location in a genome where a short nucleotide sequence is organized as a tandem repeat.

Location in a genome where a short nucleotide sequence is organized as a tandem repeat.

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This shows a theoretical example of a VNTR in two different individuals. A single strand of DNA from each individual is displayed in which there is tandem repeat sequence that the individuals share. The sequence presence is a VNTR because one individual has five repeats, while the other has seven repeats (number of repeats varies in different individuals). Each repeat is ten nucleotides, making it a minisatellite, rather than a microsatellite in which each repeat is 1-6 nucleotides.

Their analysis is useful in genetics and biology research, forensics, and DNA fingerprinting.

United Kingdom National DNA Database

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National DNA Database that was set up in 1995.

National DNA Database that was set up in 1995.

Such an approach has been advocated by the inventor of genetic fingerprinting, Alec Jeffreys.

Seal of the University of Leicester

University of Leicester

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Public research university based in Leicester, England.

Public research university based in Leicester, England.

Seal of the University of Leicester
Seal of the University of Leicester
The Fielding Johnson Building (built 1837)
Archaeologists working on the site of Richard III's grave, in the former Greyfriars Church, in September 2012
University of Leicester seen from Victoria Park – left to right: the Engineering Building, the Attenborough Tower, the Charles Wilson Building.
The Attenborough Tower, home of many of the university's arts departments
The brutalist Charles Wilson Building by Denys Lasdun
The Grade II* listed Engineering Building
The Ken Edwards Building, formerly where the School of Management was based, is now part of the School of Business.
College House, childhood home of David and Richard Attenborough
The Engineering Building, designed by James Stirling, James Gowan and Frank Newby
The Physics and Astronomy Building, part of a larger complex by Leslie Martin
Eye of Time sundial
Vaughan College, the university's former adult education college, is Grade II listed and faces the Jewry Wall Roman ruins
Leicester University Astronomical Clock
Anthony Giddens, sociologist
Peter Atkins, chemist
Sir Liam Donaldson, medical doctor and university chancellor
Natalie Bennett, British politician
Bob Mortimer, comedian

The university is known for the invention of genetic fingerprinting, and for the discovery and identification of the remains of King Richard III.

Minisatellite

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Tract of repetitive DNA in which certain DNA motifs are typically repeated 5-50 times.

Tract of repetitive DNA in which certain DNA motifs are typically repeated 5-50 times.

Discovering their high level of variability, Sir Alec Jeffreys developed DNA fingerprinting based on minisatellites, solving the first immigration case by DNA in 1985, and the first forensic murder case, the Enderby murders in the United Kingdom, in 1986.