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Why are VNTR and STR sections used in forensic DNA print analysis?
Wiki User
∙ 14y ago
Because every person has a unique number of variable number tandem repeats (VNTRs) or short tandem repeats (STRs). These sequences are non-coding DNA (doesn't code for a protein), the amount of repeats targeted on a specific chromosome can be analyzed and sorted out by length using gel electrophoresis (electric current used to separate DNA fragments by length).
If the a sample of DNA obtained from a crime scene was taken and amplified using polymerase chain reaction (PCR), multiple techniques could be performed on it. The VNTR/STRs of the sample DNA are compared to the DNA of the accused individual, if they have the same number of repeats then they are most likely guilty of the crime, but if the repeats differ by even one sequence, it cannot be assumed that the DNA definitely matches that person. These techniques help in forensic science, but a lot of accuracy in proof is needed before it can be used in a court case.
Wiki User
∙ 14y ago
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What is the VNTR area is and how is it used to profile DNA?
VNTR is variable number tandem repeats. These regions do not really mean anything to the genome but related individuals have similarities between their VNTR regions. In forensic analysis, VNTR analysis is used to place a suspect at a crime scene. IN paternity testing, VNTR information is gathered from both parents and matched to that of the child.
The two main purposes for analyzing vntr dna from dna fingerprints are matching tissues and inheritance?
The two main purposes for analyzing VNTR from DNA fingerprints are matching tissues and inheritance - This is True
Different persons have different DNA fingerprints because?
they have different numbers of the same VNTR.
What are vntr?
Variable Number of Tandem Repeats (VNTRs) definition- sites where an enzyme can cut the DNA, and the location of these sites also varies from person to person.
What are the 3 major challenges faced by geneticists?
It is very complicated and not all is used in the actual genes (actually, about 99% of it is not used). The methods for doing it include have enzymes break offnucleotides after nucleotides, however, since it only has a 99% accuracy per time, we can only get 50 nucleotide long strands before the results are meaningless. Second, most of the stuff inside genes and in between genes is not used (introns and VNTR regions and more). Third, some genes can code for multiple proteins by changing which parts inside the gene they actually use. This makes it even more difficult to figure out the genetic sequence of RNA's. Here is an online Nova program that should help you IMMENSLY, if you have the time. Parts 2,4 and 5 are the best parts. Together they take about 21 minutes, so if you have that much time, this is a must
What is the VNTR area is and how is it used to profile DNA?
VNTR is variable number tandem repeats. These regions do not really mean anything to the genome but related individuals have similarities between their VNTR regions. In forensic analysis, VNTR analysis is used to place a suspect at a crime scene. IN paternity testing, VNTR information is gathered from both parents and matched to that of the child.
The two main purposes for analyzing vntr dna from dna fingerprints are matching tissues and inheritance?
The two main purposes for analyzing VNTR from DNA fingerprints are matching tissues and inheritance - This is True
What kind of bacteria is VNTR widely used in?
tuberculosis, Leptospiosis, in Iran
Different persons have different DNA fingerprints because?
they have different numbers of the same VNTR.
What are vntr?
Variable Number of Tandem Repeats (VNTRs) definition- sites where an enzyme can cut the DNA, and the location of these sites also varies from person to person.
What is DNA fingerprint?
DNA fingerprinting (aka DNA profiling) is a scientific procedure used to determine identity or parentage using DNA. Variable Number Tandem Repeats (VNTR) are found in the nucleotides of a DNA strand. When there is a pattern of two or more nucleotides that is repeated, and the repeated patterns are directly adjacent to each other (CATCATCAT) this is a VNTR. These VNTR show up when used in gel electrophoresis, and this outcome can be used to compare DNA samples. If the pattern in the gel for a a blood sample matches the pattern in the gel for an adult, the blood most likely belongs to the adult.
Are there any vntrs trends in the general population?
In 293 nuclear families, we genotyped the INS VNTR polymorphism in 431 children and adolescents (8 to 18 years of age) and their parents. Overweight was defined according to the international definition in both children and adults.
How do DNA probes work?
These are the tiny fragments of single stranded DNA which are labelled with radioactive materials or fluorescing material with base pairs complementary to the fragments of the VNTR regions of a DNA. These are used during electrophoresis or DNA fingerprinting in order to get the position of desired DNA. For example; a VNTR region has base pair ATG, then the probe has got the base pairs TAC and a radiactive isotope, like P32 is attached to it. Now the probe combines only to those places where there are the VNTR regions. The isotope will now radiate and so the places from where radiations are received only contain the VNTRs. Hence we can specify the region. hope u'll understand:)
What are the pros and cons for DNA fingerprinting?
= Problems With DNA Fingerprinting = ---- Like nearly everything else in the scientific world, nothing about DNA fingerprinting is 100% assured. The term DNA fingerprint is, in one sense, a misnomer: it implies that, like a fingerprint, the VNTR pattern for a given person is utterly and completely unique to that person. Actually, all that a VNTR pattern can do is present a probability that the person in question is indeed the person to whom the VNTR pattern (of the child, the criminal evidence, or whatever else) belongs. Given, that probability might be 1 in 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 ProbabilityThe 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 rare VNTRs or combinations of VNTRs to create the VNTR pattern increases the probability that the two DNA samples do indeed match (as opposed to look alike, but not actually come from the same person) or correlate (in the case of parents and children).2. Problems with Determining Probability A. Population GeneticsVNTRs, because they are results of genetic inheritance, are not distributed evenly across all of human population. A given VNTR cannot, therefore, have a stable probability 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 Caucasians or African-Americans. Currently, not enough is known about the VNTR frequency distributions among ethnic groups to determine accurate probabilities for individuals within those groups; the heterogeneous genetic composition of interracial individuals, who are growing in number, presents an entirely new set of questions. Further experimentation in this area, known as population genetics, has been surrounded with and 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 DifficultiesErrors in the hybridization 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 amplification of the sample (creating a much larger sample of genetically identical DNA from what little material is 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 would minimize error, were neither stringent nor universally codified, causing a great deal of public outcry.
What are the differences between minisatellites and microsatellites?
They are usually distinguished according to the size of the repeats: Microsatellites, also termed Short tandem repeats (STRs) consist of tracts of repeats of 1-7bp, and minisatellites also called (VNTR) usually contain repeats of longer length (100-several hundred bp) Minisatellites can be found in tandem arrays, but the majority are interspersed in the genome. Whilst microsatellites are found mostly in tandem repeats.
What are the 3 major challenges faced by geneticists?
It is very complicated and not all is used in the actual genes (actually, about 99% of it is not used). The methods for doing it include have enzymes break offnucleotides after nucleotides, however, since it only has a 99% accuracy per time, we can only get 50 nucleotide long strands before the results are meaningless. Second, most of the stuff inside genes and in between genes is not used (introns and VNTR regions and more). Third, some genes can code for multiple proteins by changing which parts inside the gene they actually use. This makes it even more difficult to figure out the genetic sequence of RNA's. Here is an online Nova program that should help you IMMENSLY, if you have the time. Parts 2,4 and 5 are the best parts. Together they take about 21 minutes, so if you have that much time, this is a must
What is DNA Standard used for in a fingerprint?
The DNA strand of each organism has some sequence different from others, but there are some sequences which are known as "variable number tandem repeats" (VNTR), which are repeated many times in the DNA of an individual. These are basis of "DNA fingerprinting". DNA is cut with a restriction enzyme from the specific sites of these repeats. When the DNA of two samples are cut by these restriction enzymes, and run on gel electrophoresis, the band pattern can be matched or compared. Imagine what would happen if you got a sample of DNA from a crime scene and wanted to compare it with another sample, run years earlier or in another country. The gels would have been run at different times, by different people, under different conditions, so perhaps you could not be sure if the bands on the gel match or not. To solve this problem gels are run with both the samples and a reference material, which serves two purposes. Firstly it assures us that the gel has run correctly and that samples were treated correctly. Secondly it means we can determine what the bands of our test DNA mean by comparing them to the reference material. Sometimes the reference DNA is called the standard reference material (SRM) and we commonly used SRM2390 (for RFLP), SRM2391a (for PCR) and SRM 2392 (mitochondrial DNA) in DNA fingerprinting. So the skinny answer is that DNA standards are used to assure the quality and comparability of the test performed.
