SIBLING DNA TESTING - Brother to Brother DNA test

From the image on the left, you can see how a Father's Y chromosome is passed down to his sons. Because men have only 1 Y chromosome (and woman have none), means that 2 brothers will always have the exact same Y chromosome if they have the same biological father, or else if they are related via their paternal line.

To test to see if the Y chromosomes are identical, we use modern DNA analysis techniques to pin-point many specific areas of the Y DNA in each brother.Each specific area we investigate is different between unrelated persons, so by testing multiple areas the odds are extremely high that only related persons will match in every area we test.

Note: Remember that 2 men with the same Y may not be brothers...they could be father-son, uncle-nephew, cousins, etc. Having the same Y means you have the same male lineage (same male ancestor). So, keep that point in mind for Y DNA tests. It does also mean the Y test can be used for many other relationship tests.

If you wish to test brothers to find if they have the same biological mother, then we need to perform a Mitochondrial DNA test.

Mitochondrial DNA is only passed from Mother to child, not from Father to child, so siblings with the same mother all have the exact same Mitochondrial DNA sequence.

Click here for more detailed information about Mitochondrial DNA and the test we offer.