The most viewed preprints this month were:

• Thoughts on: Probabilities of Fitness Consequences for Point Mutations Across the Human Genome. Cooper et al. dispute some technical aspects of a paper by Gulko et al. on predicting deleterious mutations.
• Author post: Probabilities of Fitness Consequences for Point Mutations Across the Human Genome. Adam Siepel describes the story behind the Gulko et al. paper.
• Second-generation PLINK: rising to the challenge of larger and richer datasets. Chang et al. describe a new and much faster version of the popular software package PLINK.
• Ancestry Composition: A Novel, Efficient Pipeline for Ancestry Deconvolution. Durand et al. describe the ancestry inference pipeline used by the personal genomics company 23andMe.
• An extended reply to Mendez et al.: The ‘extremely ancient’ chromosome that still isn’t. On this surface, this paper by Elhaik et al. appears to be a debate about estimates of the Y chromosome mutation rate. Look just a bit deeper, however, and what this paper is “about” becomes considerably less clear.