What is the Difference Between DNA Fingerprinting and DNA Profiling

The main difference between DNA fingerprinting and DNA profiling is that DNA fingerprinting is a molecular genetic method that allows the identification of individuals according to the unique patterns of DNA, whereas DNA profiling is a forensic technique used in both criminal investigations and parentage testing. Furthermore, DNA fingerprinting focuses on VNTRs including both minisatellites and microsatellites while DNA profiling mainly focuses on STRs, which are microsatellites. 

DNA fingerprinting and DNA profiling are two methods of molecular methods that allow the identification of individuals based on their genetic makeup. 

Key Areas Covered 

1. What is DNA Fingerprinting
     – Definition, Process, Importance
2. What is DNA Profiling
     – Definition, Process, Importance
3. What are the Similarities Between DNA Fingerprinting and DNA Profiling
     – Outline of Common Features
4. What is the Difference Between DNA Fingerprinting and DNA Profiling
     – Comparison of Key Differences

Key Terms 

DNA Fingerprinting, DNA Profiling, PCR, RFLP, STRs, VNTRs

What is DNA Fingerprinting 

DNA fingerprinting or genetic fingerprinting is a molecular biology method that allows the identification of individuals depending on their genetic makeup. It was independently developed by Dr. Jeffrey Glassberg in 1983 and the British geneticist  Sir Alec Jeffreys in 1984. The original approach of Jeffreys was based on the RFLP analysis of minisatellite DNA. Thus, RFLP analysis is one of the main techniques used in DNA fingerprinting. RFLP analysis requires a large amount of DNA, generally more than 25 ng, and this DNA must be fairly intact.

Figure 1: DNA Fingerprinting Procedure

Furthermore, in classic DNA fingerprinting, restriction enzymes cut DNA from the samples into small pieces. Then, the digested DNA can be separated by Gel electrophoresis and the resulting fragments can be immobilized on to a membrane by Southern blot. After that, these fragments can hybridize with the radio-labeled DNA probes containing minisatellite. Oligonucleotide sequences can also be used as probes, and they may directly hybridize to the DNA fragments on the gel. Moreover, the size of the restriction fragments differs depending on the number of repeats of minisatellites, which is unique to an individual. Therefore, the visualization of the fragments allows the identification of the individual. 

Figure 2: VNTR Variation

Furthermore, AFLP is a faster method than RFLP as it uses the PCR amplification of VNTRs of different alleles. 

What is DNA Profiling 

DNA profiling or genetic profiling is the forensic technique important in the identification of individuals. It is important in parentage testing as well. Further, this method was developed by Sir Alec Jeffreys in conjunction with Peter Gill and Dave Werrett of the Forensic Science Service (FSS) to compare the DNA profiles of the criminal suspects. Moreover, DNA profiling nowadays is a simple and automated process, which is more statistically straightforward.

Figure 3: Parentage Testing

Moreover, DNA profiling focuses on using a panel of multi-allelic STR markers, which are structurally analogous to the original minisatellites. However, STRs are much shorter in comparison to the minisatellites; therefore, it is easier to amplify them with multiplex PCR.  STRs are the repeats of four bases. It is possible to amplify them using sequence-specific primers. Then, gel electrophoresis or capillary electrophoresis separates the resulting fragments. Generally, it is possible to analyze up to 30 STRs in a single capillary electrophoresis injection. Although the number of their alleles is very small, STRs are highly polymorphic. Normally, similar STR alleles occur in around 5-20% of individuals. 

Forensic Marker 

There are two sets of STR markers that comply with the standards requested by the criminal databases around the world. They are the European standard set of 12 STR markers and the US CODIS standard of 13 markers. Their partial overlap produces another standard, which is 18 STR markers in the Australian database.  

Linkage Markers 

The analysis of linkage markers is a unique application of forensic genetics. Generally, two of such analysis include Y chromosome analysis and mitochondrial DNA analysis.  Y chromosome analysis is important when the female victim has excess DNA from a male perpetrator in a lower proportion. In contrast, mitochondrial DNA analysis is important in samples with low levels of nuclear DNA. 

Similarities Between DNA Fingerprinting and DNA Profiling 

• These are two molecular methods involved in the identification of individuals depending on their genetic makeup. 
• Moreover, they focus on polymorphic regions of the genome that are mainly minisatellites or microsatellites. 
• PCR is one of the main techniques used in both methods. 
• Both methods can use biological samples such as blood, hair, semen, etc. for the extraction of DNA.  

Difference Between DNA Fingerprinting and DNA Profiling 

Definition 

DNA fingerprinting refers to the analysis of DNA to identify individuals, while DNA profiling refers to the analysis of individuals’ DNA characteristics for forensic studies. 

Importance 

Moreover, DNA fingerprinting is a molecular genetic method that allows the identification of individuals according to the unique patterns of DNA, while DNA profiling is a forensic technique important in both criminal investigations and parentage testing.  

Type of DNA Sequences

DNA fingerprinting focuses on VNTRs including both minisatellites and microsatellites while DNA profiling mainly focuses on STRs, which are microsatellites.  

Techniques Involved in the Process 

RFLP, AFLP, and PCR are the three techniques widely used in DNA fingerprinting, while PCR is the main technique used in DNA profiling. 

Characteristics 

While DNA fingerprinting is a cumbersome method with many steps, DNA profiling is a simple process, which can be automated. 

Conclusion 

DNA fingerprinting is the laboratory technique to identify individuals according to their genetic makeup. Generally, it uses the analysis of VNTRs of the genome with the help of molecular biology techniques, including RFLP, AFLP, and PCR. In contrast, DNA profiling is the forensic technique of identification of individuals. However, it is based on the analysis of STR regions of the genome with the use of PCR. Therefore, DNA profiling is a simple and easy technique. It is also important in parentage testing. Hence, the main difference between DNA fingerprinting and DNA profiling is the method and uses. 

References:

1. Roewer, Lutz. “DNA fingerprinting in forensics: past, present, future.” Investigative genetics vol. 4,1 22. 18 Nov. 2013, doi:10.1186/2041-2223-4-22.

Image Courtesy:

1. “Stages of Gene Fingerprinting” By Sneptunebear16 – Own work (CC BY-SA 4.0) via Commons Wikimedia    
2. “D1S80Demo” By PaleWhaleGail at English Wikipedia (CC BY-SA 3.0) via Commons Wikimedia     
3. “DNA paternity testing en” By Helixitta – Own work based on work File:Test na ojcostwo schemat.svg by Pisum (CC BY-SA 3.0) via Commons Wikimedia