Science Focus - the home of BBC Science Focus Magazine

Can a DNA test differentiate between a person's father and brother?

Subscribe to BBC Science Focus Magazine and get 6 issues for just £9.99

Get your genetic tests at the ready.

Asked by: Sofia, Manchester

Advertisement

Yes. You inherit exactly half of your father's genes, so checking 16 genetic markers on both of you is enough to be 99.99 per cent confident that someone is your father. Brothers also share half their genes with their other siblings, but only on average - the exact relatedness varies. By comparing lots more genetic markers, a DNA test can show that two siblings are very closely related but can't be father and son (or father and daughter) because the genetic relatedness isn't exactly 50 per cent.

Read more:


Advertisement

Subscribe to BBC Focus magazine for fascinating new Q&As every month and follow @sciencefocusQA on Twitter for your daily dose of fun facts.

Authors

luis villazon
Luis VillazonQ&A expert

Luis trained as a zoologist, but now works as a science and technology educator. In his spare time he builds 3D-printed robots, in the hope that he will be spared when the revolution inevitably comes.

Advertisement
Advertisement
Advertisement

Sponsored content