SUBMITTED TO, SUBMITTED BY,
DR. KALIKA KUHAR MEGHAVI DABAS
LECT. RDT 1208927
DEPT. BIOTECHNOLOGY 5th semester /3rd yr
BIOTECHNOLOGY
Introduction
* DNA FINGERPRINTING method of identification that compares fragments of DNA. Sometimes called DNA TYPING.DNA is the genetic material found within the cell nuclei of all living things .In mammals the strands of DNA are grouped into structures called CHROMOSOMES. With the exception of identical twins , the complete DNA of each individual is unique.
* A DNA FINGERPRINTING is constructed by first extracting a DNA sample from body tissue or fluids such as hair, blood , saliva. The sample is then segmented using enzymes,& the segments are arranged by size using a process called electrophoresis. The segments are marked with probes & exposed on a x-ray film ,where they form a characteristic pattern of black bars of the DNA FINGERPRINT. If the DNA FINGERPRINT produced from two different samples match , the two samples probably came from the same person.
* DNA FINGERPRINTING was first developed as an identification technique in 1985.Originally used to detect the presence of genetic diseases , DNA fingerprinting soon came to be used in criminal investigations and forensic science.The first criminal conviction based on DNA evidence in the United States occurred in 1988.The criminal investigation ,DNA fingerprints derived from evidence collected at the crime scene are compared to the DNA fingerprints of suspects . The DNA evidence can implicate or exonerate a suspect.
The Dissertation on DNA Fingerprinting – Paper
DNA Fingerprinting It is widely known that each individual has a DNA profile as unique as a fingerprint. ... which produced large amounts of the DNA segments. These segments could then be purified and labeled ... evidence obtained the course of routine investigation." Criminal lawyer Majeed Memon said, "If the courts ... in turn benefit by being able to sample, hear, download and share songs with friends ...
* In the United States ,the FBI has created a national database of genetic information called NATIONAL DNA INDEX SYSTEM. The database contains DNA obtained from convicted criminals and evidence found at crime scenes. Some experts fear that this database might be used for unauthorized purposes ,such as identifying individuals with stigmatizing illnesses such as acquired immunodeficiency syndrome(AIDS).
MAKING DNA FINGERPRINTS
LABORATORY PROCEDURE THAT REQUIRES SIX STEPS-
1:ISOLATION OF DNA : DNA must be recovered from the cells or the tissues of the body .only a small amount of tissue-like blood ,hair ,or skin is needed .For example ,the DNA found at the root of hair is usually sufficient.
2:CUTTING ,SIZING,AND SORTING: special enzymes called restriction enzymes are used to cut the DNA at specific places .for ex-an enzyme called EcoRI ,found in bacteria ,will cut DNA only when the sequence GAATTC occurs .The DNA pieces are sorted according to size by a sieving technique called electrophoresis .The DNA pieces are passed through a gel made from seaweed agarose ( a jelly –like product made from seaweed).
This technique is the biotechnology equivalent of screening sand through progressively finer mesh screens to determine particle sizes.
3:TRANSFER OF DNA TO NYLON: the distribution of DNA pieces is transferred to a nylon sheet by placing the sheet on the gel and soaking them overnight.
4-5:PROBING:adding radioactive or cooled probes to the nylon sheet produces a pattern called the DNA fingerprint. Each probe typically sticks in only one or two specific places on the nylon sheet.
The Term Paper on Concepts Of DNA Fingerprint And Forensic Analysis
... DNA Profile Database There are also controversies in the storage of DNA data of suspects and criminals. The main difference between fingerprint databases and DNA fingerprint ... is a sequence in the DNA strand. The fragmented strands of DNA are then separated using a process called electrophoresis, which ... are short custom built pieces of DNA, are used to seek portions from the DNA evidence to be used ...
6:DNA FINGERPRINT: the final DNA fingerprint is built by using several probe(5-10 or more)simultaneously. It resembles the bar codes used by grocery stores scanners.
DNA PROFILING
Also called DNA testing, DNA typing, or DNA genetic fingerprinting) is a technique employed by forensic scientists to assist in the identification of individual on the bases of their respective DNA profiles.DNA profiles are encrypted sets of numbers that reflected a person DNA makeup , which can also be used as the persons identifier. DNA profiling should not be confused with full genome sequencing.
Although 99.9% of human DNA sequences are the same in every person’s identifier .DNA PROFILING uses repetitive sequences that are highly variable called variable number tandom repeats (VNTR).
VNTRs loci are very similar between closely related humans , but so variable that unrelated individuals are extremely unlikely to have the same VNTRs . The DNA profiling technique was first reported in 1985 by Sir Alec Jeffreys at the University of LEICESTER in England, and is now the basis of several national DNA databases.
(In the non-coding regions of the genome, sequences of DNA are frequently repeated giving rise to so called VNTRs. The no. Of repeats varies between different people and can be used to produce their genetic fingerprints. In the figure person A has only 4 repeats while person B has 7.When their DNA is cut with the restriction enzyme EcoRI, which cuts the DNA at either end of the repeated sequences (in this example), the DNA fragment produce by B is nearly twice as big as the piece from A ,as shown when the DNA is run on a gel (right).The lane marker pieces of DNA that help us to determine the sizes . If lots of pieces of DNA are analysed in this way, a , fingerprint comprising DNA fragments of different sizes ,unique to every individual, emerges).
USES OF DNA FINGERPRINTS
DNA fingerprints are useful in several applications of human health care research, as well as in the justice system.
DIAGNOSIS OF INHERITED DISORDERS
DNA fingerprinting is used to diagnose inherited disorders in both prenatal and newborn babies in hospitals around the world .These disorders may include cystic fibrosis, haemophilia, Huntington’s disease familial Alzheimer’s, sickle cell anaemia, thalessemia, and many others .Early detection of such disorders enables the medical staff to prepare themselves and parents for proper treatment of child. In some programs, genetic counsellors use DNA fingerprint information to help prospective parents understand the risk of having an affected child .In other programs, prospective parents use DNA fingerprint information in their decisions concerning affected pregnancies.
The Essay on Student Exploration: Dna Fingerprint Analysis
Student Exploration: DNA Fingerprint Analysis Vocabulary: codon, DNA, DNA fingerprint, genotype, identical twins, nitrogenous base, phenotype, trait Prior Knowledge Questions (Do these BEFORE using the Gizmo. ) 1. The two navy officers shown at left are identical twins. Why do you think identical twins look so similar? Identical twins look so similar because identical twins have the same genetic ...
DEVELOPING CURES FOR INHERITED DISORDERS
Research programs to locate inherited disorders on the chromosomes depend on the information’s contained in DNA fingerprints. By studying the DNA fingerprints of relatives who have a history of some particular disorder, or by comparing large groups of people with and without the disorders, it is possible to identify DNA Patterns associated with the disease in the question. This work is a necessary first step in designing an eventual genetic cure for these disorders.
BIOLOGICAL EVIDENCE
FBI and police labs around the U.S. have begun to use DNA fingerprints to link suspects to biological evidence-blood or semen stains, hair, or items of clothing-found at the scene of a crime. Since 1987 Hundreds of cases have been decided with the assistance of DNA fingerprints in the court system is to establish paternity in custody and child support litigation .In these applications, DNA fingerprints bring an unprecedented, nearly perfect accuracy to the determination.
PERSONAL IDENTIFICATION
Because every organ or tissue of an individual contains the same DNA fingerprints, the US armed services have just begun a program to collect DNA fingerprints from all personnel for use later, in case they are needed to identify causalities or persons missing in action. The DNA method will be far superior to the dog tags, dental records and black typing strategies currently in use.
PRACTICAL APPLICATIONS OF DNA FINGERPRINTING
1. PATERNITY & MATERNITY
Because a person inherits his or her VNTR’S from his or her own parents ,VNTR patterns can be used to establish paternity & maternity .The patterns are so specific that a parental VNTR pattern can be reconstructed even if only the childrens VNTR patterns are known (the more children produced ,the more reliable the reconstruction).Parent child VNTR pattern analysis has been used to solve standard father identification cases as well as more complicated cases of confirming legal nationality and, in instances of adoption ,biological parenthood.
The Term Paper on DNA Profiling Techniques in Forensic Science
Abstract Since 1985, DNA profiling in forensic science has become very important in this virtual era of technology and in the world of science that solves both major and minor crimes. Small traces of DNA are considered in all circumstances from how the DNA was collected to fully obtaining the profile in its significant form. Traces of sweat, blood and semen are the most common type’s evidence ...
2 . CRIMINAL IDENTIFICATION AND FORENSICS
DNA isolated from blood , hair ,skin ,cells, or other genetic evidence left at the scene of a crime can be compared ,through VNTR pattern ,with the DNA of the criminal patterns, with the DNA of the criminal suspect to determine guilt of innocence. VNTR pattern are also useful in establishing the identity of a homicide victim ,either from DNA found as evidence or from the body itself .
3. PERSONAL IDENTIFICATION
The notion of using DNA fingerprints as a sort of genetic barcode to identify individuals has been discussed but this is not likely to happen any time in the foreseeable future .The technology required to isolate ,keep on file ,and then analyse millions of very specified VNTR patterns in both expensive and impractical social security numbers ,picture ID ,and other more mundane methods are much more likely to remain prevalent ways to establish personal identification.
PROBLEMS WITH DNA FINGERPRINTING
Like nearly everything else in the scientific world , nothing about fingerprinting is 100% assured. The term DNA fingerprint is , in one sense, misnomer it implies that ,like a fingerprint ,the VNTR ,pattern for a given person is utterly & completely Unique to that person. Actually ,all that a VNTR pattern (of that child, the criminal evidence, or whatever else) belongs .Given, that probability might be 1 & 20 billion, which would indicate that the person can be reasonably matched with the DNA fingerprint ; then again that probability might only be 1 in 20 ,leaving a large amount of doubt regarding the specific identity of the VNTR pattern’s owner.
1. GENERATING A HIGH PROBABILITY
The probability of a DNA fingerprint belonging to a specific person needs to be reasonably high-especially in criminal cases , where the association helps establish a suspect’s guilt or innocence. Using certain rate VNTRs or combinations of VNTRs to create the VNTR pattern increases the probality that the two DNA samples do indeed match or correlate.
The Essay on Cause Of Crime Person Criminals Complex
Criminals are born as with a different psychological scheme that persuades them to commit crime. Scientists believe that criminals develop such a complex from either a biological, however not genetic, chemicals in their body. These differences allow a psychological failure that leads the person not to develop a conscience. However, there are two types of criminals those who feel absolutely no ...
2.PROBLEMS WITH DETERMINING PROBABILITY
A. Populations genetics
VNTRs because they are results of genetics inheritance , are not distributed evenly across all of human population. A given VNTR cannot , therefore, have a stable probalilty of occurrence ,it will vary depending on an individual’s genetic background. The difference in probabilities is particularly visible across racial lines. Some VNTRs that occur very frequently among Hispanics will occur very rarely among caucasions or African-americans. Currently, not enough is known about the VNTR frequency distribution among ethnic groups to determine accurate probabilities for individuals within those groups; the heterogeneous genetic composition of interracial, individual, who are growing in numbers; present an entirely new set of questions. Further experimentation in this area, known as population genetics, has been surrounded with hindered by controversy, because the idea of identifying people through genetic anomalies along racial lines comes alarmingly close to the eugenics and ethnic purification movements of the recent past, and, some argue, could provide a scientific basis for racial discrimination.
B. TECHNICAL DIFFICULTIES
Errors in the hybridizations and probing process must also be figured into the probability, and often the idea of error is simply not acceptable. Most people will agree that an innocent person should not be sent to jail, a guilty person allowed to walk free, or a biological mother denied her legal right to custody of her children, simply because a lab technician did not conduct an experiment accurately. When the DNA sample available is minuscule, this is an important consideration, because there is not much room for error, especially if the analysis of the DNA sample involves amplifications of the sample (creating a much larger sample of genetically available), because if the wrong DNA is amplified (i.e. a skin cell from the lab technician) the consequences can be profoundly detrimental. Until recently, the standards for determining DNA fingerprinting matches, and for laboratory security and accuracy which minimize error, were neither stringing nor universally codified, causing a great deal of public outcry.
The Essay on The pros and cons of DNA profiling
Does DNA profiling in its current state offer foolproof identification? What needs to be in place for it to be error-free? Should all incarcerated criminals be forced to give samples? Should convicted juveniles? Should the general public be required to give a DNA sample? The pros of DNA profiling are that it can be used to quickly eliminate a suspect, saving time in searches for perpetrators. And ...
