Detecting the form of selection from DNA sequence data

Clues to our evolutionary history lie hidden within DNA sequence data. One of the great challenges facing population geneticists is to identify and ac curately interpret these clues. This task is made especially difficult by t he fact that many different evolutionary processes can lead to similar obse rvations. For example, law levels of polymorphism within a region can be ex plained by a low local mutation rate, by selection having eliminated delete rious mutations, or by the recent spread to fixation of a beneficial allele , Theoretical advances improve our ability to distinguish signals left by d ifferent evolutionary processes. In particular, a new test might better det ect the footprint of selection having favored the spread of a beneficial al lele.