Because of the growth of the population, world social have committed many crime offences as well. The law needs to control the social order and bring peace to human society. Commonly, science has helped to solve the legal problems in communities. As Simon A. Cole and Michael Lynch stated that “Forensics is the “silent witness,” it “never lies,” and it cannot misremember or be biased or bribed.” “Forensic science is often seen as an applied science used in criminal investigations and criminal trials.” Not only, a minor crime but also serious crimes, the DNA technology can help to identify criminal problems of the United States and the world such as transnational crime, terrorism , and illegal migration. In Thailand, the DNA technology has shown a major role in important events in the country.
2.7 Polymerase Chain Reaction (PCR) In 1971, Dr. Har Gobind Khorana’s group described the idea to amplify a DNA (Templeton, 1992). Later on in 1985, Kary B. Mullis invented the Polymerase Chain Reaction (PCR) which is used today in different fields, such as scientific research, clinical diagnostics and criminal investigations. PCR is a molecular biology tool that is used to amplify a fragment of DNA to generate thousands to millions of copies. This technique is based on an enzymatic reaction which is controlled by thermal cycling, where every cycle consists of heating and cooling steps. The generated DNA fragments after every cycle are used as templates for the next cycle.
These two events significantly increased the use of DNA analysis in forensic science. Interpol (2014) developed guidelines that related the best practice of human remain identification following situations that stemmed from the forensic community. Interpol is a global police organization that enables police in various different countries to simultaneously work at making the world a safer place for everyone. Forensic DNA databases are an important investigative resource used in the modern day justice system. The computerized storage of DNA profiles as part of a database allows the systematic matching of crime scene samples with personal profiles.
At each PCR cycle it is possible to measure the amount of amplified product. The detection is performed using non-specific fluorescent dyes that intercalate with any double-stranded DNA or using sequence-specific DNA probes. After each cycle, to estimate the DNA concentration, the fluorescence is measured with a detector and is compared with a control used as reference. Given its capacity to detect the presence and abundance of a specific DNA sequence, RT-PCR techniques have been developed to quantify HPV-DNA in clinical samples (Molijn et al. 2005) and (Dutra et al.
DNA methylation also occurs during the differentiation of adult cells. In both instances, methylation takes place almost exclusively on cytosine bases adjacent to a guanine, a combination called a CpG dinucleotide. Many of these dinucleotides are clustered in regions, called CpG islands, located in and near promoter sequences adjacent to genes. Islands adjacent to essential genes (housekeeping genes) and cell-specific Genes are unmethylated, making these genes available for transcription. Other genes with adjacent methylated CpG islands are transcriptionally silenced.
1.Polymerase chain reaction (PCR): Polymerase chain reaction is a method of DNA or RNA amplification . The PCR method allows millions of copies to be created from a very small DNA section. The PCR methodology was developed in 1983 by Kary Mull , who in 1993 received a Nobel Prize for Chemistry with Michael Smith PRINCIPLE & PROCEDURES: 1.DNA denaturation. Once the DNA has been isolated and purified from the cell, a PCR assay can begin. Uncleaned DNA can also be used for PCR, but it is ineffective.
PCR applications are helpful in diagnosis of majority of hereditary or non heritable diseases, this technique is also applied in molecular biology and microbiology to identify certain bacteria and viruses that can cause serious health problems. Applications of PCR in forensic science are also widely used now a days because only small amount of DNA samples are needed to diagnose several medical conditions. Qualitative PCR can of course be used to detect not only human genes but also genes of bacteria and viruses. One of the most important medical applications of the classical PCR method is therefore the detection of pathogens. Many viruses contain RNA rather than
The bacteria were heat-killed, and these respective components were extracted and the composition resulted in being similar to that of DNA. They also treated the bacteria with multiple enzymes, such as trypsin, chymotrypsin, ribonuclease and deoxyribonucleodepolymerase, where it was found that only the deoxyribonucleodepolymerase inhibited the formation of smooth Pneumococcus colonies. [Downie. A. W. (1972)] Thus, they confirmed that DNA was the transformation principle in Griffith's experiments. The Avery and MacLeod experiment was replicated in the laboratories at the University of the Witwatersrand.
Homologous recombination (HR) can be explained as a process where DNA is exchanged or copied between two chromosomes or different regions of the same chromosome. The process requires homology between the exchanging DNA regions. Homologous recombination repairs DNA breaks, especially double stranded breaks (DSBs), stabilizes and repairs stalled forks. HR consists of a series of inter related pathways that function in repair of DNA breaks (Figure 4). Initially, stretches of single stranded DNA (ssDNA) are resected at the stalled forks or DSB ends which are quickly bound by replication protein A (RPA).
There aren’t many human cloning machines around, but there are still machines that clone other things. The whole process of cloning revolves around nuclear transfer. Human cloning is heavily being used to duplicate an embryo, also it’s been used to clone has been used to clone livestock and even plants. The idea that is going to change the world all started in 1885 by a German scientist named Hans Spemann. According to Utah Genetics Hans spemann was the first person to split an embryo and went on to win a Nobel Prize in physiology and medicine in 1935 for discovering the organizer effect on embryo splitting.
From that point on, new nucleotides are added to each of the original strands (A to T, C to G) until the result is two identical sequence copies of DNA. 3. How is DNA information used to synthesize polypeptides? A gene or protein is used to make polypeptides. In order to create this gene, transcription and translation must take place to create a protein from DNA.
In the late 1980s, the federal government laid the groundwork for a system of the national state, stored local DNA databases for the storage, and exchange of DNA profiles. At every stage of development, all of the cells forming the body contain the same DNA half and a half from mother and father. Now they 're going to use every DNA they have possible have and use it on each person to see whom is not innocent or is found guilty. This fact allows the relationship and test using all the samples including loose cells from the cheeks collected using swabs and everything they could to find out the DNA The combination of marker sizes found in each person makes up his or her unique genetic profile. They 're still
What role does the Polymerase Chain Reaction (PCR) play in producing a DNA Profile? PCR amplifies the regions of DNA with short tandem repeats and uses primers with fluorescent labels. This works by replicating the region of DNA several times. The same region is also amplified on both chromosomes, however they are different sizes, which are then put into gel