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Macdonald SJ, Long AD.Macdonald SJ, et al.Proc Natl Acad Sci U S A. 2005 May 3;102 Suppl 1(Suppl 1):6614-21. doi: 10.1073/pnas.0501990102. Epub 2005 Apr 25.Proc Natl Acad Sci U S A. 2005.PMID: 15851675Free PMC article.