The number of copies of the gene encoding a ligand for an HIV co-receptor have been found to influence the susceptibility to HIV infection and AIDS progression. New studies dispute this onclusion. The studies are contested by the authors of the original findings, and highlight the inherent difficulties in accurately measuring gene copy numbers (pages 1110-1112, 1112-1115,1115-1117 and 117-1120). © 2009 Nature America, Inc. All rights reserved.
