DNA Relationship Testing
Checks Kinship

A DNA relationship test can confirm that two people are related.

For example, an adoptee finds her presumed birth family. But the birth parent is not available for a paternity test. The adoptee can confirm the relationship by testing a potential half sibling.

That’s what I did in my own adoption search.

Another example occurs when a child’s alleged father dies without a paternity test. The man’s parents may wish to know if they are the child’s biological grandparents.

There are two types of DNA relationship testing that can answer such questions. Both methods depend on the principle that closely related people have more DNA in common than unrelated people.

DNA Kinship Testing

Also called sibling testing, this is the traditional DNA test to show that two people are related.

The test compares two or more potential siblings on a small set of autosomal markers. Autosomal markers reflect the genetic contribution of both parents.

This form of DNA relationship testing cannot be as conclusive as a paternity test. That’s because there is no way to tell which marker came from which parent.

In certain situations supplemental tests of the subjects’ X or Y chromosomes can provide additional proof of relationship. Testing additional family members may provide further clarification.

See DNA Kinship Testing for more details on this type of test. On that page I’ll tell you which company is my recommended lab for DNA kinship testing.

Autosomal DNA Testing

An alternative test type emerged in late 2009. That’s when 23andMe introduced their Relative Finder. Early in 2010 Family Tree DNA followed with their Family Finder.

Both are examples of Autosomal DNA Testing. This type of test is far more conclusive than traditional Kinship Testing.

These tests each check more than a half million pairs of locations in your autosomal DNA. By measuring the number and length of common DNA segments, these tools can tell if you are full siblings, half siblings, first cousins etc.

Since you need to buy two tests for relationship testing, price is a significant factor. Family Finder from Family Tree DNA is less expensive. The tests from 23andMe provide additional information on Ancient Ancestry and health traits that you may or may not wish to pay for.

See Relative Finder for more details on that test. And see Autosomal DNA Comparison for a more detailed comparison of the two tests.

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