There are two major testing options for brother to brother DNA tests:
Are you testing to see if you have the same father or the same mother (or both)?
1. Y chromosome DNA testing - Brothers testing for the same father
Accuracy of 99.9+%
To see if two or more male persons have the same biological father. (If you wish to know if they have the same mother, you will require a Full Sibling to Sibling DNA Test)
Only men have a Y chromosome, and a father will pass exactly the same Y chromosomal DNA to all his sons. Therefore, 2 brothers with the same biological father will always have exactly the same Y DNA patterns.
Note: If 2 men share the same Y chromosome, this shows that they share the same paternal line - so they could be father-son, uncle-nephew, cousins, etc.
Summary of Y Chromosome DNA Testing Costs:
DNA Test
Accuracy
Cost
Order
Brother
to Brother
(2 persons)
99.9%
£230
OR
2. Full sibling to sibling DNA testing. Brothers testing for the same mother and father
Accuracy of 99.9+%
To establish whether or not two brothers have the same mother (and father)
Uses DNA statistics to evaluate the amount of DNA sharing and to deduce a biological relationship. Full siblings have a lot more DNA in common than half siblings. Half siblings share more DNA than unrelated persons.
For a higher accuracy, include the mother's DNA sample (from both or either brother).
Summary of Y Chromosome ( Full Sibling ) DNA Testing
Costs:
