DNA is deoxyribonucleic acid, which is found in almost all living things. DNA serves as a code for the creation and maintenance of new cells within an organism. Within humans, it is found in almost every cell. Although most of our DNA is found within the nucleus of our cells as nuclear DNA, a very small amount of our DNA is also found within the mitochondria as mitochondrial DNA. Because mitochondrial DNA is generally not used for solving crimes, for the purpose of this paper it will be disregarded.
DNA is a long curved structure, made up of pairs of four specific bases: adenine, guanine, cytosine, and thymine, is the repository of a code from which all of our cells are made. The code is made up of base pairs which look like the
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Although DNA was initially observed by Frederich Miescher, a German biochemist near the end of the nineteenth century, the key to the structure of DNA was not discovered until almost a hundred years later. It was at that time that science realized the importance of DNA to the study of biology.
In 1953 four scientists: James Watson, Francis Crick, Maurice Wilkins and Rosalind Franklin completed a DNA model which they created using observed X-ray diffraction patterns. This model showed how the structure of DNA was able to transmit genetic information from parents to their offspring.
The work of these four people led to a complete restructuring of the beliefs of the scientific community regarding genetic information. Their initial word led to further work which encompassed their hypothesis of how DNA replicates itself. From this work came the modern technologies of DNA fingerprinting and sequencing.
DNA fingerprinting is a technique that is used to determine how likely it is whether genetic material came from a specific person or family group. Since 99% of human DNA is identical, that means that it is only 1% of our DNA which is different, and it is that 1% that we look at when we are attempting to determine the origin of a DNA sample.
Enzymes are applied to DNA to break it into smaller pieces which are called restriction endonucleases. These restriction endonucleases become
Understanding DNA can take a lot of studying and confusion to even get the general idea of the concept. The structure of DNA is very complicated and complex to understand, but researchers James Watson, Francis Crick, Maurice Wilkins, and Rosalind Franklin all developed the idea of the DNA structure in 1953. Deoxyribonucleic Acid is found in the nucleus of the cell. It is a double stranded molecule that contains the genetic code and is the main component of chromosomes. DNA is the blueprint of organisms. Nucleotides are the basic unit of DNA and they are made up of sugar, phosphate, and one of the four basis including adenine,
DNA forensics is a division of forensic science that focuses on the use of genetic material in criminal investigation to answer questions pertaining to legal situations, including criminal and civil cases. Through DNA testing, law enforcement officers are able to identify human remains or the individual responsible for a crime. DNA testing is a highly advanced scientific process that involves replicating the human DNA sequence to create a genetic map of an individual. Because of its reliability, DNA testing has become a significant factor in criminal cases. However, it has also been identified as having the potential to violate privacy and constitutional rights. The DNA identification process consists of five stages. These five stages
From cases such as OJ Simpson to Chandra Levy, DNA profiling also called DNA fingerprinting or DNA typing has played a major role in the criminal justice system. The law enforcement community uses DNA profiling to rule out or identify suspects. Unlike hair microscopy, bite mark comparisons, shoe print comparisons, and firearm tool mark analysis, DNA typing has been developed through massive scientific research and has undergone meticulous scientific evaluation (Innocence Project). DNA is a foolproof method of identifying a perpetrator of a crime.
Deoxyribonucleic acid, or DNA as it is most commonly known, is a strand of molecules found within the cell nucleus of all living things. It is called a “genetic fingerprint” because each is different to the other and everyone, apart from identical twins, have
DNA per medical dictionary is defined as A nucleic acid that carries the genetic information in cells and some viruses, consisting of two long chains of nucleotides twisted into a double helix and joined by hydrogen bonds between the complementary bases adenine and thymine or cytosine and guanine. DNA sequences are
Throughout the early 19th and 20th century, many scientists have studied deoxyribonucleic acids in order to attain higher understanding over the matter. Johann G. Mendel had figured out and understood the laws of heredity. Friedrich Miescher amazingly discovered DNA in 1869, even though scientists did not understand DNA was the genetic material
In the early 1950s, the race to find the structure of DNA was in full swing. The search was being conducted at three different colleges. At the California Institute of Technology, Linus Pauling,
In Time Magazine an article states On February 28 1953, James Watson and Francis Crick broke the DNA code and discovered that the DNA strand is double helix and forms like a ladder. They found that cytosine and guanine were paired together and that adenine and thymine were paired. They discovered the building block of life (Wright, 1999). DNA is found in all living organisms.
DNA, Deoxyribonucleic Acid, is the basic structure for all life, it is the blueprint, the instruction manual, on how to build a living organism. DNA is made up of four nitrogen bases, adenine, thymine, cytosine, and guanine which are connected by sugar-phosphate bonds. Through a process called Protein Synthesis, the nitrogen bases are the code for the creation of amino acids. Essentially, DNA makes amino acids, amino acids make proteins, proteins make organisms. This process has been taking place for much longer than scientists have been able to document. Those scientists are called geneticists and their field is genetics.
Law Enforcement keep notes on arrests that have founded people innocent of crimes, and retention of an innocent person's DNA can be charge or otherwise, seen as a invasion of that person’s privacy and civil liberties. Dr. Alec Jeffrey, a former professor at the University of Leicester laboratory, consulted with his lawyers to develop the new type of technique called DNA profiling. His technique would prove that DNA fingerprinting (profiling) can individualize evidence compared to the blood typing. DNA profiling compares 13 standard STRs to form a profile. The analysis used by the scientists, uses PCR and STRs to profile an individual. It is highly unlike that two individuals’ identical numbers of repeats for all 13 STRs, will match, which DNA fails is hardly never due to a successful match of 385 million to 1. This makes DNA profiling the most accurate tool in Forensics.
DNA structure is composed of a double helix, constituting two strands twisted around one another. Each strand have a linear arrangement of building blocks called nucleotides or bases (adenine, thymine, cytosine and guanine). These strands
In 1928, Frederick Griffith performed the first major experiment that led to the discovery of DNA by studying two strains of the pneumococcus bacteria. Of the two strains he studied, one caused pneumonia (lethal) and had a smooth appearance while the other strain did not cause pneumonia (non-lethal)
Rosalind Franklin’s work on DNA was crucial in discovering the composition of the human body as a whole. Her x-ray photo revealed a double helix structure and she also discovered the A and B form of DNA. She worked through the adversity of being a female in a predominately male dominated realm and made remarkable findings that were eventually stolen. She adapted to a new lab with antiquated technology. Before this discovery, the structure of DNA was thought to be simple. Scientist, Watson and Crick, started with the wrong structure of DNA from a misinterpretation of notes from one of Franklin’s presentations. Unlike Watson and Crick, Rosalind Franklin could explain DNA and how it worked.
The four people who discovered the structure of DNA built upon the EXPLORATION AND DISCOVERY of others:
Due to the DNA’s specificity, samples can be utilised for identification. DNA is a nucleic acid composed of deoxyribose sugar bound to a phosphate group and one of four nitrogenous bases (adenine, guanine, cytosine and thymine). Each section of these three components are referred to as nucleotides, which are joined to the phosphate or sugar of another nucleotide by strong covalent bonds to form a backbone. The nitrogenous bases are joined to complimentary bases of another nucleotide (adenine with thymine, guanine with cytosine) to create a double stranded molecule (Figure 2). To complete the double helical structure, the molecule coils to compact it’s contents. DNA molecules can contain up to two million base pairs, with a human genome containing approximately 3 million base pairs. The random assortment of nitrogenous bases as well as the numerous mutations within certain DNA sequences, results in genetically diverese DNA molecules and genomes between individials.