We are all 50th cousins

Cousins ​​test

Cousins ​​test

Price: N / A
Testing of: Cousins
Duration: not specified

A cousin DNA test aims to find out if first degree cousins ​​are biologically related. International Biosciences receives many requests for cousin tests, but does not currently offer them. The reason for this is that cousin DNA testing will invariably give inconclusive results.

Why are cousin DNA tests inaccurate?

DNA testing of cousins ​​is so inaccurate because of the inheritance patterns of genes in a family. For example, we know that children share around 50% of the genes of their biological mother or father. Aunts and uncles share approximately 25% of their genes with their nieces and nephews. So when it comes to first-degree cousins, they only share about 12.5% ​​of their genes, i.e. 87.5% of their genetic makeup deviates from one another. Even tests between aunts / uncles, in which the participants share around 25% of their genes, can be a challenge for DNA laboratories due to the comparatively low percentage match of the DNA profiles with their nieces and nephews. With only 12.5% ​​shared DNA between first-degree cousins, it's only up to luck whether the DNA profiles have anything in common at all. Based on the knowledge of genetics, we share a lot of DNA with anyone, and when cousins ​​share DNA it is impossible to determine whether it is pure coincidence or inheritance.

Although some companies offer DNA testing among cousins, these cannot provide conclusive results either because DNA testing technologies do not currently allow this. We recommend that you do not have cousin DNA tests done by any company.

What are the options for testing among cousins?

There are many tests that are better suited to determining the relationship between suspected relatives. The following tests will give more accurate results:

Paternity and Maternity Tests: Often times, cousins ​​want to have a cousin DNA test because they want to know if a parent (mother or father) is also their biological parent. The idea is that any matching genes in the cousins ​​indicate that they were inherited from a common blood relative (one cousin's biological parent would be the other cousin's aunt or uncle). If people really want to know whether their mother or father is their biological parent, consider taking a paternity or maternity test before considering testing another relative.

DNA testing among male cousins: If there are two male cousins ​​who want to know if they are related through the paternal line, a Y chromosome test can help. This test is highly accurate and if the men tested have the same Y chromosome profile, they also share the paternal bloodline.Click here for more information.

Aunt / Uncle Test: Testing uncles or aunts with their nieces or nephews can prove whether there is a biological relationship between the people tested or not. The result of the test will provide the so-called uncle / aunt index. An index higher than 1.00 implies that the people are related. An index lower than 1.00 means that there is no relationship. An index of exactly 1.00 would not be unique. Click here for more information on the uncle / aunt test.

Cousins ​​and their maternal lineage

Cousins ​​who want to know whether they have a female relative in common can have what is known as the X-SV test. The test analyzes the maternal inherited mtDNA and if the people tested have the same mtDNA profile, this indicates a common maternal relative.

MtDNA, or mitochondrial DNA, is inherited from the mother to her male and female offspring. All women pass on their mtDNA to their children. Men, on the other hand, do not pass their mtDNA on to their offspring. The birth of a male offspring thus interrupts the line of mtDNA. In other words, the subjects tested must have an uninterrupted detectable maternal line in order to have the mtDNA test performed.