Re: Can a DNA test distinguish paternity between brothers?

Carla,

The short answer to your question is, most likely.  The brothers have the 
same parents and probably share some alleles at some loci, however, their 
genetic profiles will be unique.  And since so many loci are examined (we 
look at 13 loci)the probablility that they would pass on the same alleles 
at each locus would be astronomical.  In other words, there must be at 
least one locus in which only one brother could have passed on the genetic 
information found in the child, thereby eliminating the other brother as 
being the father.

Dale Laux
Forensic Scientist