DNA fingerprinting

DNA fingerprinting (often incorrectly referred to as DNA analysis) is a molecular biological method used to identify specific, unalterable individual DNA patterns. This method makes it possible to attribute the tested cellular material to a specific person with a certain statistical probability. This method is used, for example, in paternity tests and in criminal investigations.

DNA is the carrier of genetic material, the genetic makeup. DNA is primarily located in the cell nucleus, specifically within the chromosomes. In classical DNA fingerprinting, the DNA is first cleaved using restriction enzymes, and the resulting fragments are separated by electrophoresis. Gene probes are used primarily to detect and visualize repetitive DNA sequences.

Today, these regions are analyzed using the polymerase chain reaction (PCR). This is a method in which specific sections of a DNA strand can be artificially amplified in virtually any quantity. By labeling the corresponding products (e.g., with fluorescent dyes), they can be detected directly; a probe for detection is not required. This method increases detection sensitivity many times over compared to classical DNA fingerprinting.

Significance

In doping analysis, DNA fingerprinting could be used to individualize urine samples (i.e., to assign a urine sample to a specific person). However, there is little need to use this method, as the unambiguous assignment of a sample to a person is ensured by a strictly regulated sample collection procedure (sealing, code number, sample protocol, etc.).

However, the DNA fingerprinting method has been used to provide additional confirmation of sample tampering that had been detected using the steroid profile method (1).

References

1. Berschick, P., Geyer, H., Schänzer, W.: Individualization of urine samples in doping control by steroid profiling and PCR-based DNA analysis. In: B. Olaisen, B. Brinckmann, P.J. Lincoln (eds.): Progress in Forensic Genetics 7, Elsevier Science (1998) 171–173.