Researchers have wondered why some regions of DNA that do not code for proteins but nevertheless are functionally important have sequences that have not been maintained by evolution. It could be because evolution is instead working to conserve the DNA's structure, say Elliott Margulies at the National Human Genome Research Institute in Bethesda, Maryland, Thomas Tullius at Boston University in Massachusetts and their colleagues.
A DNA helix can have subtle structural variations in its grooves and its physical arrangement that affect how well proteins bind to it. By comparing a portion of DNA structure across 36 different species, the team estimates that 12% of the human genome is conserved — twice the estimate based on sequence conservation. The method should help to identify new non-coding regions with important biological roles.
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Genomics: Staying in shape. Nature 458, 262 (2009). https://doi.org/10.1038/458262e