1. Testing to see if a brother and sister have
the same Mother - Use a Mitochondrial DNA test.
Mitochondrial DNA is only passed from mother to children.
So all siblings to the same mother will have the exact
same mitochondrial DNA. For more detailed information
click to see our Mitochondrial
DNA page.
2. Testing to see if a brother and sister have
the same Father - Use a Full Sibling to Sibling
DNA test
A brother to sister (sibling to sibling DNA Test) works
by testing a very large number of different DNA points
(known as loci) in each person. Full siblings share
a lot more DNA in common than do unrelated persons,
and also, half siblings share more DNA in common than
unrelated persons, but not as much as full siblings.
So this test looks at the amount of DNA sharing and
uses DNA statistics to evaluate the amount of DNA sharing
to deduce biological relationship.
Because we are evaluating the amount of DNA sharing,
it is helpful to have DNA from any parents or other
siblings of the persons being tested, since that drastically
helps the evaluation process by allowing us to pin-point
exactly which DNA is more likely to have come from each
sisters Father in particular.
If you want to test 2 brothers then you may have a
cheaper option of testing only the Y chromosome, click
for brother to brother testing options. If you are
wishing to test only sisters, then you should click
for our sister to sister
page. |
