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 conclusion. 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 1117–1120).
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References
Sebat, J. et al. Science 305, 525–528 (2004).
Wain, L.V., Armour, J.A. & Tobin, M.D. Lancet 374, 340–350 (2009).
Lee, J.H. & Jeon, J.T. Cytogenet. Genome Res. 123, 333–342 (2008).
Urban, T.J. et al. Nat. Med. 15, 1110–1112 (2009).
Bhattacharya, T. et al. Nat. Med. 15, 1112–1115 (2009).
Field, S.F. et al. Nat. Med. 15, 1115–1117 (2009).
He, W. et al. Nat. Med. 15, 1117–1120 (2009).
Modi, W.S. Genomics 83, 735–738 (2004).
Moore, J.P. & Klasse, P.J. Cell Host Microbe 2, 281–283 (2007).
O'Brien, S.J. & Moore, J.P. Immunol. Rev. 177, 99–111 (2000).
Gonzalez, E. et al. Science 307, 1434–1440 (2005).
Kuhn, L. et al. AIDS 21, 1753–1761 (2007).
Shalekoff, S. et al. J. Acquir. Immune Defic. Syndr. 48, 245–254 (2008).
Dolan, M.J. et al. Nat. Immunol. 8, 1324–1336 (2007).
Ahuja, S.K. et al. Nat. Med. 14, 413–420 (2008).
Shostakovich-Koretskaya, L. et al. AIDS 23, 679–688 (2009).
de Smith, A.J., Walters, R.G., Froguel, P. & Blakemore, A.I. Cytogenet. Genome Res. 123, 17–26 (2008).
Yoon, S., Xuan, Z., Makarov, V., Ye, K. & Sebat, J. Genome Res. 19, 1586–1592 (2009).
Korbel, J.O. et al. Science 318, 420–426 (2007).
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Shrestha, S., Tang, J. & Kaslow, R. Gene copy number: learning to count past two. Nat Med 15, 1127–1129 (2009). https://doi.org/10.1038/nm1009-1127
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DOI: https://doi.org/10.1038/nm1009-1127