Directory enquiries http://generic-vardenafil.in.net/ levitra  When the National Institutes of Health approached the Smithsonian Institute about doing a human genome exhibit at the Natural History Museum in Washington, D.C. in 2011, the NIH thought it had good timing: 2013 marks the 10th anniversary of the sequencing of the human genome, and the 60th anniversary of James Watson and Francis Crick's discovery of DNA's structure.