Polymorphism levels in serial transfer evolution experiments (Evolution); also described with clarity in a Stanford CEHG blog post by Dr. Doc Edge.
Raw Materials: Mutation, Recombination, Gene Duplication
What determines the distribution of allele frequencies in humans in large samples? We found surprising effects of two evolutionary forces, mutation rate variation and fitness epistasis. (PLoS Genetics)
Also see a highlight of the paper at F1000Prime.