Can the police search for ancestral DNA?

How accurate are genetic tests for genealogy?

Find an ancestor with spit? DNA analyzes for origin research are very popular. However, privacy advocates and biologists are not exactly enthusiastic.

The stories go to the heart: siblings, separated by adoption, are in each other's arms for the first time, a staunch Brit, who by his own admission doesn't like Germans, is purified when he learns that he has five percent German roots and one young Kurdish woman learns that one of the many strangers in the room is her Turkish cousin. “These tests should be compulsory,” cheers a young French woman who just hated the British and who - thanks to the English genes she has just discovered - suddenly sees herself as an ambassador for international understanding.

Such videos can be found in abundance on the Internet. They advertise DNA tests to research their origins. Origin analyzes of this kind are very popular in the USA, Australia and many other classic immigration countries. But the market is also growing in Germany. How do the tests work, what do they cost and what are their advantages and disadvantages? Our editorial member Sibylle Kranich is investigating these questions here.

How does such a test work?

Anyone who has decided on a provider can order their sampling kit via the Internet. After a few days, the small box will be in the mailbox. This includes the necessary utensils and very simple instructions for use. Depending on the company, you send back a cotton swab with a swab of the oral mucosa or a test tube into which you have put some saliva. The return is already franked.

There are many different companies around the world. Two in particular are active on the German-speaking market: “Myheritage” and “Ancestry”. Of course, it is also possible to buy a test kit from other companies. Their websites are mostly only in English and there are a few other differences.

In America and other countries, companies also offer tests on a subject's complete DNA. He can then, for example, learn about genetic defects or predispositions to certain diseases. This is not allowed in Germany. The Genetic Diagnostics Act precisely regulates which examinations are permitted and which can only be carried out under medical supervision.

It is very different. But you can expect costs between 50 and 100 euros. Often - especially now at Christmas time - there are special offers. Tests from abroad that offer more extensive analyzes can cost up to 1,000 euros.

Then what happens to my sample?

In the laboratory, the genetic material is isolated from the cells and the sequence of chemical letters that make up all genes is read using very precise procedures. By comparing the sequence of letters, different genes and changes in a gene can be precisely identified.

How long does the evaluation take?

That depends on the provider. One speaks of three to four weeks, the other of six to eight. The analysis is carried out by a laboratory. After the evaluation, the results can be viewed online. To do this, you have to log in with the profile you have already created for the order.

What is the result?

The user is presented with a very clear breakdown by percentage. For example, it says: German-speaking regions of Europe 64 percent, England and north-western Europe 18 percent, Northern Italy 12 percent and so on. The regions of origin are also marked in color on a world map.

What else does the package include?

The test looks at two things. An origin analysis tries to find out where the ancestors of the customers come from and where in the world possible relatives live. In addition, it is checked whether there are any further matches with other DNA samples that are available in the provider's database. If there are significant similarities in the genome, then there is a high probability that it is a direct relative.

How meaningful are the tests?

Geneticists warn against taking the results too seriously. The tests analyze selected DNA segments and compare them with reference data. For close relatives - up to a fourth cousin, for example - this works very well. However, when it comes to recognizing exactly where your own DNA was in the past, it becomes difficult. You can only see where and how often certain variants occur and thus assign which regions your current genome corresponds to how much.

“We assign it as it is most likely. The percentages are only an approximate estimate, ”said human geneticist Mark Stoneking in an interview. Mark Thomas, Professor of Evolutionary Genetics at University College London, is even clearer: In an article for the English "Guardian" he compares the validity of the tests for genealogy with that of horoscopes.

Who will benefit from the tests?

The business of genetic origin research is very lucrative for providers. In doing so, they are often accused of receiving double payments. By collecting the data of their customers and then selling them to other companies. At least one American company made the data available to the police. In their privacy policy, MyHeritage and Ancestry ensure that personal information is safe with them. German privacy advocates have serious doubts.