Frequently the only biological material available to identify persons or find next of kin is DNA in a very degraded state. In these cases, the kits usually employed to carry out DNA identifications do not produce very positive results, given that all the DNA is not available, and that which is available is highly fragmented. Biochemist Adrian Odriozola has developed a tool for identifying persons from these small fragments of DNA. His thesis, presented at the University of the Basque Country (UPV/EHU), is entitled Developing molecular tools for analysis of highly degraded DNA samples.
In order to develop this tool, Dr Odriozola used sequences known as STR (short tandem repeat). These are sequences of small fragments of DNA that are continuously repeated and turn out to be highly useful for distinguishing between persons, due to the fact that the number of repetitions of the sequence varies according to the individual. Precisely, the kits that Odriozola investigated and that are currently employed in Forensic Genetics are based on STR analysis. However, they fail when the DNA is degraded, and so the researcher drew up a new route for analysing STRs, taking these conditions into account. Thanks to this line of research, Dr Odriozola has been able to publish a number of articles together with research colleagues at the UPV/EHU, in publications such as the International Journal of Legal Medicine. The University has also been granted two patents.
Working with shorter sequences
To carry out identification using DNA, it is first of all essential to undertake millions of copies of the fragment to be analysed (a process called amplification); in this case, of the STRs, which are obtained using the PCR (polymerase chain reaction) technique. So that PCR can function, primers have to adhere themselves to the two ends of each of the STR sequences. In this way, on undertaking PCR, copies are obtained of both the STR sequ
|Contact: Amaia Portugal|