What is DNA profiling?
DNA profiling uses molecular genetics to distinguish one species, animal or human being from another. The methods are routinely used worldwide in investigations of crime scenes, missing person cases, identification of remain after major tragedy also paternity testing (Kluftinger, J. and Plunket, R., 2015). The relatedness of animals in the determination of species in the evolutionary tree. There are many different types of tissue that DNA can be extracted from, such as, blood, hair, bones, skin, soft tissue, saliva, fur and semen.
The differences between the DNA from one person to another is very minimal, in humans more than 99% of DNA does not vary (Kluftinger, J. and Plunket, R., 2015). The coding regions of DNA generally have important functional values and therefore are maintained human to human. The small amount of DNA that does change are polymorphic sequences and these are used for forensic applications. The polymorphic sequences that are chosen for forensic analysis are also known as anonymous sequences, these sequences are derived from regions of DNA that do not code for any known proteins or control for any known traits. This enables the confidentiality and privacy of the people who are under investigation.
The differences between the DNA from one person to another is very minimal, in humans more than 99% of DNA does not vary (Kluftinger, J. and Plunket, R., 2015). The coding regions of DNA generally have important functional values and therefore are maintained human to human. The small amount of DNA that does change are polymorphic sequences and these are used for forensic applications. The polymorphic sequences that are chosen for forensic analysis are also known as anonymous sequences, these sequences are derived from regions of DNA that do not code for any known proteins or control for any known traits. This enables the confidentiality and privacy of the people who are under investigation.
How do we determine the type of analysis for the DNA?
Two important categories of tandem repeat have been used widely in forensic genetics: minisatellites, also referred to as variable number tandem repeats (VNTRs); and microsatellites, also referred to as short tandem repeats (STRs). The general structure of VNTRs and STRs is the same. Variation between different alleles is caused by a difference in the number of repeat units that results in alleles that are of different lengths and hence tandem repeat polymorphisms are known as length polymorphisms (The Council for Responsible Genetics).
The choice in the protocol all depends on the quantity and quality of the DNA that is isolated.
If there is a lot of DNA then it is possible to do restriction fragment length polymorphism (RFLP) analysis.
If there is a little amount of DNA available then the DNA can be amplified by polymerase chain reaction (PCR).
Once the DNA is amplified either variable number tandem repeat (VNTR) analysis or short tandem repeat (STR) analysis can be used.
If you have a small amount of DNA that is of questionable quantity then STR analysis is the preferred method of analysis. VNTR analysis can only be used if you have several hundred base pairs of DNA that is intact and in the correct order regions in order to perform the analysis.
In forensic investigation is that when anyone enters a crime scene they can leave traces of their own DNA and to ensure that the DNA found on site is of the suspect and not the investigator(s).
The choice in the protocol all depends on the quantity and quality of the DNA that is isolated.
If there is a lot of DNA then it is possible to do restriction fragment length polymorphism (RFLP) analysis.
If there is a little amount of DNA available then the DNA can be amplified by polymerase chain reaction (PCR).
Once the DNA is amplified either variable number tandem repeat (VNTR) analysis or short tandem repeat (STR) analysis can be used.
If you have a small amount of DNA that is of questionable quantity then STR analysis is the preferred method of analysis. VNTR analysis can only be used if you have several hundred base pairs of DNA that is intact and in the correct order regions in order to perform the analysis.
In forensic investigation is that when anyone enters a crime scene they can leave traces of their own DNA and to ensure that the DNA found on site is of the suspect and not the investigator(s).