Need help distinguishing between a primary and secondary source
Too long for a comment: Although this is a review article which summarizes the findings of other researchers, considers this as a primary article. The author gives you all the resources he used in the reference section of this article and summarises their finding. Additionally, review articles in renowned journals (and Genome Research is definitely such a journal) are peer-reviewed. Primary vs. secondary sources would be more the comparision of research articles and news articles. In my observation, news articles hardly ever name the sources or the original articles about which they report. Plus they sometimes have problems of getting the message wrong.