Is genetic memory real?

Fact or fiction?The genetic model

Lennart Pyritz: What can actually be read from a sample?

Michael Stang: In principle a lot, because the long-term goal of forensic medicine, police and public prosecutor's office is to create an exact phantom image from a biological trace. But much of this is still a long way off, because a large part of the methods is still in the research or experimental stage, and there are also legal barriers. So far, in Germany such forensic genetics analysis can only be used to determine gender based on externally visible features.

Pyritz: If many methods are not yet routine in daily police work or in forensic medicine, which ones have the potential to soon find their way into everyday investigations?

Rod: There are a number of different methods that deal with the genetic recognition of external characteristics. Far ahead are methods that can genetically determine hair color, eye color and skin color, especially if there are no mixed colors, such as green eye color. Some of these methods have very good hit rates: a light skin color can even be determined with an accuracy of 99.9 percent, red hair with an accuracy of 97 percent. The aim is to get more than 98 percent in all examinations. Then these methods could perhaps also be used legally at some point. Then there are research projects that are very promising but are only just beginning, such as determining the shape of the face, the shape of the hair, whether someone has freckles, the ear lobes are exposed or have grown on, and there are also genetic markers that show whether or not someone has a dimple in their chin. And there are approaches to determining body height and age.

1.5 million unassigned crime scene traces in the European DNA database

Pyritz: Which parts of the genome are the researchers concentrating on?

Rod: These new methods deal with so-called SNPs, which are single nucleotide polymorphisms, i.e. variations of a single base pair in a DNA strand. These variations are inherited, the researchers now know more than 10 million different SNPs and, depending on the frequency and combination in a person's genome, they represent certain external characteristics. Sometimes even 10 different SNPs are sufficient to determine the skin color, several hundred are needed to determine the height of the skin.

Pyritz: You mentioned earlier that there are legal hurdles. Did the forensic scientists at the conference today give the impression of frustration that they could, but are not allowed to, find out a lot more?

Rod: In discussions before and after the lecture that was partly discussed, that is, "if we are allowed to do what we can", but it is clear to everyone that the methods must be safe, the law also protects the citizens and everything only in cooperation with Police work and justice is allowed to happen. What is clear, however, is that the number of criminal offenses is enormous - the European DNA database now contains 1.5 million unassigned crime scene traces, that is, genetic profiles of people who are not known. One could find out a lot, - as far as theoretically - the Cologne public prosecutor's office, which was represented at the conference, of course did not issue a statement, because the legal framework for such investigations has not been clarified in Germany. In other countries like the Netherlands, however, it does.

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