Kriminalistinė biologija: istorija, dabartis ir ateitis

Abstract

The history of forensic biology is strictly connected with two names – Karol Landsteiner who in 1901 discovered blood types in an ABO system. The other one is Alec Jeffreys who in 1985 came upon polymorphic minisatellite sequences and invented the “DNA fingerprinting” technique1. These two separated by time events allow us to understand the road forensic biology followed to become the discipline without which it is impossible to find the offenders. For years serological examinations and enzymes polymorphism analysis has been used to study biological evidence. Nevertheless in many cases such as the situations where changes were caused by natural deterioration processes, physical or chemical factors, the “age” of biological traces left on a crime scene it happens to be impossible to obtain satisfying results. These limitations, however, do not apply to genetic studies. Blood, sperm, saliva are very good sources of DNA. A smaller amount of DNA content in hair, teeth or bones is compensated by greater resistance against unfavourable external factors. The introduction of DNA analysis allowed for the use of the upper skin layer (epidermis) cells in forensic examinations. Prior applied serology methods had not offered such possibilities. It is possible to use also the samples obtained as a result of an autopsy. However, it is worth remembering that the quantity of degraded genetic material grows proportionate to the longevity of post mortem time2. On some occasions, DNA could be found in the tissues preserved and covered in paraffine. In the end, it is worth mentioning that at the current state of advanced technology and the possibility of applying different examination techniques it is possible to analyse every type of biological trace.