Fingerprinting, DNA

Replace the prehybridization solution with hybridization solution containing approximately 10 counts min ml of purified, labelled DNA probe. Allow hybridization to proceed at 55°C (for M13) or 62°C (Jeffreys probes) overnight with shaking. 

Wrap each membrane individually in film (e.g. Saranwrap , Genetic Research Instrumentation Ltd). 

Fix the membranes in autoradiography cassettes and place two X-ray films over them. Keep the sealed cassettes at -80°C (the period of exposure required is determined by developing top film after 12 h of exposure). 

Label the final autoradiographs and store in a dry, dust-free envelope. 

Note Hybridized nylon membranes should not be allowed to dry out and can be dehybridized, for repeat probing, by two 30-min washes at 45°C, firstly in 0.4 M NaOH and secondly in 0.2 M Tris (pH 7.5) plus 0.1% SDS and x 0.1 SSC (as recommended by the manufacturer of Hybond N membrane. Amersham International). 

In 1985, Jeffreys [144] discovered that certain sections of human DNA were so characteristic that they alone could be used to identify a suspect, in a manner superior to that of traditional fingerprinting. From this, a highly successful forensic identification technique has been evolved and is now widely used by law enforcement agencies. It is based on the analysis of those parts of human DNA known as mini satellites (satellite DNA). These are characterised by relatively short sequences of about a dozen base pairs which are repeated many times throughout the whole DNA (Chapter 14.3). Minimal samples are required, and a single cell may provide enough DNA for an absolutely positive identification of an individual.  

It has been suggested that tissue samples be taken from all convicted felons to allow for identification of their presence at future crime sites by DNA fingerprinting (Section 13.7). This may seem very desirable, but some ethical and constitutional questions must first be answered. Nevertheless, DNA testing has been used to determine whether people currently in custody might have been involved in unsolved crimes. One crime frequently examined in this way is rape, because body fluids are usually left behind. Many unsolved crimes are being solved, and some convicted prisoners are being found innocent. In at least one bizarre case, a felon was found innocent of the crime for which he was in jail, only to be rearrested in a few weeks because his DNA matched samples found on rape victims in three other cases. 

The power of DNA testing cannot be overemphasized. In the trial of O. J. Simpson, the identity of the DNA was never questioned, although the defense successfully raised questions as to whether the evidence had been planted. In most cases, DNA evidence results in the release of innocent suspects in a crime. 

When the DNA matches, however, the rate of plea bargaining goes up, and the crimes are solved without long and expensive court trials. 

The DNA markers found in a child must arise from either the mother or the father. A man who is suspected of being the father of a particular child is immediately excluded from consideration if that child s DNA contains markers that are not found in the DNA of the mother or the suspect father. It is more difficult to prove conclusively that a person is the father of a particular child because it is usually too expensive to test enough markers to provide conclusive proof. However, in cases in which there are only two or three candidate fathers, it is usually possible to determine the correct one. 

These polymorphisms (a word meaning many shapes ) are analyzed via gel electrophoresis to separate the fragments by size, followed by blotting and the anneahng of a probe for a specific sequence. 

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DNA fibers DNA fingerprinting DNA gyrase DNA ligase DNA ligases DNA polymerase... 

Perhaps the most common and well-publicized use of DNA fingerprinting is that carried out by crime laboratories to link suspects to biological evidence— blood, hair follicles, skin, or semen—found at a crime scene. Thousands of court cases have now been decided based on DNA evidence. 

Coconut oil, composition of, 1062 Coding strand (DNA), 1108 CODIS, DNA fingerprint registry, 1118... 

DMF, see Dimethylformamide DM SO, see Dimethyl sulfoxide DMT (dimethoxytrilyl ether), DNA synthesis and, 1114 DNA, see Deoxyribonucleic acid DNA fingerprinting, 1118-1119 reliability of, 1119 STR loci and, 1118 Dopamine, molecular model of. 930 Double bond, electronic structure of, 16... 

The many millions of DNA molecules in the cells of your body are identical to each other. That is, the base sequence in all of these molecules is the same. In contrast, the base sequence of the DNA molecules in every other person in the world differs at least slightly from yours. In that sense, your "DNA fingerprint" is unique. 

At least in principle, comparison of DNA fingerprints can determine the guilt or innocence of a suspect beyond a reasonable doubt. 

A DNA fingerprint can be used for many purposes other than solving violent crimes. In particular, it can serve to identify deceased individuals. In June of 1998 the "Vietnam Unknown" buried in the Tomb of the Unknown Soldier at Arlington National Cemetery was identified by DNA technology. He was shown to be First Lieutenant Michael Blassie, shot down over Vietnam in May of 1972. DNA samples taken from his mother matched those obtained from his body. A month later Blassie, a native of St. Louis, Missouri, was reburied in a national cemetery located in that city. 

Maltseva O, P Oriel (1997) Monitoring of an alkaline 2,4,6-trichlorophenol-degrading enrichment culture by DNA fingerprinting methods and isolation of the responsible organism, haloalkaliphilic Nocardioides sp. strain M6. Appl Environ Microbiol 63 4145-4149. 

There have been a number of attempts to achieve this objective, but so far the challenge has not been fully met. This Chapter will examine some of the conventional approaches and then go on to consider how recent developments in the use of the Polymerase Chain Reaction (PCR) with DNA for the identification of species and individual organisms by DNA analysis, sometimes known as DNA Fingerprinting", have identified a yet unrealized need for a new dimension of certified reference materials. 

D. Redecker, T. Batinic, I. S. Feder, K. Koseh, U. Schulz, P. Vinuesa, and D. Werner, Biocontrol strain Pseudomomis fluorescens W34 specific detection and quantification in the rhizo.sphere of Cucumis salivus with a DNA probe and characterization by DNA fingerprinting. 2. Natmforsch. 54c 359 (1999). 

Bandi, C., La Rosa, G., Bardin, M.G., Damiani, G., Comincini, S., Tasciotti, L. and Pozio, E. (1995) Random amplified polymorphic DNA fingerprints of the eight taxa of Trichinella and their comparison with allozyme analysis. Parasitology 110, 401-407. 

Tautz, D. (1993) Notes on the definition and nomenclature of tandemly repetitive DNA sequences. In Pena, S.D.J., Chakraborty, R., Epplen,J.T. and Jeffreys, A.J. (eds) DNA Fingerprint State of Science. Birkhauser Verlag, Basel, Switzerland, 21 pp. 

Walton, S.F., Currie, B.J. and Kemp, D.J. (1997) A DNA fingerprinting system for the ectoparasite Sarcoptes scabiei. Molecular and Biochemical Parasitology 85, 187-196. 

Suzuki S, Takada T, Sugawara Y, Muto T and Kominami R. 1991. Quercetin induces recombinational mutations in cultured cells as detected by DNA fingerprinting. Jpn J Cancer Res 82(10) 1061—1064. 

This activity is intended to be performed in conjunction with Experiment 66. Restriction endonucleases, or restriction enzymes, cleave DNA at specific base sequences, fragmenting the DNA into smaller pieces. The two strands of a DNA double helix are cleaved at different places, resulting in uneven fragments called sticky ends. Cleavage of DNA by restriction enzymes is a required first step in various types of DNA analysis, including DNA fingerprinting and recombinant DNA technology. 

We have maintained the same balance of information in the new chapter and therefore details of specific applications of techniques are not discussed, for example, DNA fingerprinting. Where appropriate, we have included titles of books which have an emphasis on applications in the further reading list at the end of each chapter. These lists are not intended to be fully comprehensive, nor are the chapters referenced as we consider this to be inappropriate for the level of potential readership. 

RFLP analysis by the Southern blot procedure and detection with probe specific for each VNTR are the basis of DNA fingerprinting. Using just four DNA probes, paternity can be excluded with a cumulative probability of 99.9% (J2). 

J2. Jeffrys, A. J., Brookfield, J. F. Y., and Semeonoff, R., Positive identification of an immigration test-case using human DNA fingerprints. Nature (London) 317, 818-809 (1985). 

Allele-specific oligonucleotide Specific alleles of a gene Genetic counseling and DNA fingerprinting... 

I. Paternal relationship between a man and infant can best be determined by the technique commonly referred to as DNA fingerprinting. Which of tbe following sequences is most conveniently analyzed in a DNA fingerprint ... 

That much of the human genome has no apparent function is not the same as saying that it has no use. In fact, we have been able to exploit the apparently nonfunctional DNA for several purposes. A good deal of this DNA consists of repeated sequences of bases. There is, for example, a more-or-less 300 base pair sequence termed Alu that is found at more than 500,000 positions in the human genome. The frequency of Alu repeats and their location in the human genome varies from person-to-person and acts as a DNA fingerprint. These and other repeats provide the basis for the use of biotechnology in forensic science. 

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