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The DNA fingerprinting technology is one of the most widely used technique in all fields. Especially in this report we discuss about the applications of DNA fingerprinting in botany, applications in zoology and in forensics. We also get a brief knowledge about the origination of DNA fingerprinting and its development in various sciences and in various fields. DNA profiling is also discussed in depth in this report. Their applications in convicting criminals are also discussed in depth in this report.
DNA finger printing is an extensive technique that enables scientists to match small tissue samples and facilitates research studies on the composition, reproduction and on plants, animals evolution. In particular for identification of criminals that is plays an important role in forensic sciences.
DNA FINGERPRINTING IN ZOOLOGY:
Thomas Kuhn in 1962 argued that the progress of scientific knowledge finally results from periodic paradigm shifts during a period of crisis in which new ideas dramatically influences the status quo. This is generally true though. Alec Jeffrey's' identification of hyper variable repeat motifs in the human beta-globin gene along with the subsequent development of new technology known today as DNA fingerprinting finally resulted in a extensive shift in the life sciences such as ecology, evolutionary biology and mainly in forensics. The variation jeffreys identified has been utilised to recognize individuals from not only humans but also many animal species. In addition, the technology has been widely used to determine an individual's sex as well as paternity or maternity along with kinship.
For many scientists this was the opportunity to enhance their skills in molecular biology.
Due to restriction enzyme digestion of an individual's tandem repeat loci unique DNA fingerprints arise. In case of individuals belonging to sexually outbreeding populations, the outcome of multilocus DNA profiles are distinctively variable and unique to the individual.
Jeffreys strategy or technique finally resulted in a change in the discipline of zoology because it became apparent that DNA fingerprinting could also be applied to other animal species and birds. The first application of DNA fingerprinting with two reports were published on mating systems in passer domesticus commonly called as house sparrows. This resulted and showed a significant advance over the degree of genetic resolution. Which was available earlier by isozyme based techniques. This allowed true genetic relationships among organisms to be determined rather being inferred from field observations. Which uncovered many secrets and surprises like finding that many species are inferred by significant levels of extra pair paternities along with maternities. The discovery that was done in Malurus cyaneus commonly called as Australian superb fairywren about 75 percent matings consisted of extra pair copulations.
DNA finger printing also made scientists to test predictions of kin selection models in a an effective manner. Species hybrids were also detected by using multilocus profiles. Similar methods were adopted to describe evolution and population structure though the success enhance using single locus methods.
Finally we get to know that minisatellite DNA fingerprinting has produced spin off technologies like non invasive determination of sex.
The first protocols for showing multilocus DNA fingerprints utilised relatively long minisatellite DNA probes like VNTR. Probes were hybridised restriction enzyme resolved DNA that has been centrifuge and attached to a nylon membrane. These early probes had concatenates short core of 16 bp repeats that were found to be highly conserved and spread throughout the genome.
Multilocus, minisatellite probe analysis also known as DNA fingerprinting required relatively more amounts of high quality, high molecular weight, genomic DNA resolved with an appropriate restriction enzyme. When two parents and thir offspring were evaluated a clear pattern of inheritance was observed generally.
DNA FINGERPRINTING IN BOTANY:
Alec jeffreys' published his seminal nature papers on the use of minisatellite probes for DNA fingerprinting of humans. This was done three decades ago. For many organisms including pants this new technology was utilised. Everybody ecstatic about the exclusive method that allowed us to discriminate between humans, animals, plants and fungi for the first time on the individual level using genetic DNA markers. Since these years methodologies have encountered a fast evolution and variegation. More many techniques were developed which improved diversification and distinction between plants and other organisms. By the advent of PCR has enhanced the development of PCR based single or multi locus profiling strategies in the second phase. Whereas first phase was taken over by restriction fragment analysis along with southern blot hybridization. Third phase actually dates earlier to 2005. When several noble,highly parallel DNA sequencing strategies were developed that enhanced the whole over current sanger sequencing technology equal to a thousand fold and more.
FINGERPRINTING PLANTS IN THE PAST:
Botany consists of many disciplines dependent on the ability to differentiate among plant genotypes. A neutral and objective tool was given by molecular markers which were based on isoenzymes. These are the enzymes that catalyze the likewise chemical reaction but vary in aminoacid sequence . This also counts the speed taken too travel through an electrophoric gel. In 1960 isoenzymes were introduced into the plant sciences and after that continuously their importance increase. Now a day's their utilisation is extensive. Co dominant allozyme information became popular . For example population structure along with gene flow and isolation by distance. It also includes mating systems and hybridization. Due to high polyphenols in leaves of some plants protein extraction was often difficult. The evaluation plants growing in poor areas was also a big problem as their proteins generally needed to get isolated and purified in a small time by sampling. Very less levels of allozyme polymorphism among related groups was the third major problem. Then came RFLP mathodology that is DNA based restriction fragment lenght polymorphism. The RFLP methodology was also first applied to the chloroplast DNA molecule. For this, DNA samples were resolved with either single or combined restriction enzymes. They were also hybridised with radiolabelled cp DNA specific probes from one of the libraries. For example petunia. Recent studies indicated that substitution rates of mt DNA can differ highly in even closely related plant species. In a paper showing different rice cultivars species oryza sativa by hybridizing resriction enzyme acted or digested rice DNA with the human 33.6 minisatellite probe.
In the same year two more papers reported minisatellite probe fingerprinting material. This time derived from the genome of phage or bacteriophage M13. The Hordeum vulgare after hybridisation with M13 probe. Rogstad and others generated similar M13 fingerprints from different separate branches of populus deltoides cammonly called cottonwood tree proving and showing somatic stability. The degree of variation is highly depended on mode of reproduction. The ability of minisatellite probes to differentiate between specimens which were produced by vegetative propagation or apomixis was demonstrated and showed in populus tremuloides commonly called north american quaking aspen. It was also demonstrated in raspberry and blackberry species along with species of rubus. In the crops which are cultivated the propagation is done either through seeds like biennials or annual crops . Vegetatively in fruit crops as well as in many ornamental plants. In the second one each cultivar is expected to have a single monomorphic genotype. Another set of RFLP produced polymorphic fragmenta patterns like in cicer arietnum commonly called as chick pea , musa paradisaca commonly called banana , lycopersicon esculentum commonly called as tomato and oryza sativa commonly called as rice. It is also produced in double haploid lines of beta vulgaris commonly called as sugarbeet.
DNA FINGERPRINTING IN FORENSICS:
DNA fingerprinting one of the legendary discoveries of late 20th century has made renaissance in forensic investigations. This review deeply shows us the 30 years of progress in forensic DNA evaluation which helps to catch criminals, exonerate wrongly accused and to convict real criminals of murder, disaster and wars. Current methods are depended on short tandem repeats along with lineage markers chromosome and mitochondrial DNA are covered and their applications are demonstrated by case examples.
Benefits of enhancing DNA databases are dealt along with their risks.
After the discovery of DNA finger printing catching real criminals has become much easier.
Lineage markers have special applications in forensic genetics. Y chromosome analysis is very helpful in cases where there is an excess of DNA from a female victim and only a low proportion from a male perpetrator. Typical examples include sexual assault withoutinvestigative genetics.
DNA finger printing, one of the famous discoveries of the 20th century has changed and enhanced forensic investigations. Current standard techniques based on some short tandem repeats also known as STRs. Lineage markers are encapsulated and their applications are shown by some case examples.
A NEW METHOD THAT CHANGED THE FORENSIC WORLD:
Alec jeffreys in united kingdom found special variable heritable patterns from repititive DNA analyzed with multilocus probes. He called the method DNA fingerprinting. This technique proved applications in many fields like botany, zoology and forensics. It is also applied in other disciplines of biology. Forensic genetic finger printing is the comparison of DNA in a person's nucleated cells with that recognized in biological matter found at the place of crime. The applications of these techniques introduces new factual evidence to convict criminals' and cases in courts.
Jeffreys new technology now obsolete for forensic use has taken place a few changes and development in terms of basic strategy and methodology like southern blot to PCR, from radioactive to fluorescent labels, from gels to capillaries.
As this technique became more sensitive the utilisation and methodology became straightforward.. But what still to be noted is that the process of DNA identification results are accepted in legal proceedings.
The radio labeled DNA probes containing minisatellite are hybridised to DNA that is restriction enzyme digested , separated using agarose electrophoresis and using southern blotting test immobilized on a membrane. After washing away excess probe the exposure to X-ray film allows these different fragments to be initialised.
DNA finger printing is a widely used technique now-a-days. We can also say it is a trending technique all over the world. As we discussed above it has application in biology and forensics. Mostly it is used in forensics to convict criminals and solve court cases. As we discussed above Alec jeffreys was the one to discover DNA finger printing. As we discussed above DNA finger printing has many changes and developments as compared to past. In many secret head quarters this DNA finger printing technique is used as a secure lock which detects our hand and matches our DNA. If our DNA matches the secure locker opens otherwise it will not open. Many studies are going on DNA finger printing to make it more flexible and easier to mankind.