Signatures of neutral evolution in exponentially growing tumors: a theoretical perspective

We investigate the site frequency spectrum in the two-type model of clonal evolution. If the fitnesses of the two types are {lambda}0 < {lambda}1 then the site frequency spectrum is c/f where = {lambda}0/{lambda}1. This is due to the advantageous mutations that produce the founders of the type 1 population. Mutations within the growing type 0 and type 1 populations follow the 1/f law. Our results show that neutral evolution can be distinguished from the two-type model using the site frequency spectrum.