Dr. David Goldstein, director of the Duke Center for Human Genome Variation, said: "'The more common a variant is, the less likely it is to be found in a functional region of the genome. Scientists have reported this observation before, but this study is the most comprehensive effort to date using annotations of the functional regions of the human genome and fully sequenced genomes.' ... He also said he was surprised by the notable consistency of the finding. 'It's not just that the most rare variants are different from the most common, it's that at every increase in frequency, a variant is less and less likely to be found in a functional region of the DNA,' Goldstein said."