If Technology Review is right, we may have to stop making fun of those DNA-based ancestry sites. According to this article, the popularity of large-scale studies like GWAS is providing markers that appear to be more indicative of actual ancestry than some of the early-days markers that have been used to date. Of course, if the ancestry companies started using high-density arrays to look at hundreds of thousands of regions across the genome ... well, then they'd just be 23andMe.