Prehistory of Potyviruses 63. McKinney HH (1937) Mosaic diseases of wheat and related cereals.: US Department of Agriculture Circular No. 442. pp 1–23. 64. Ho SY, Phillips MJ, Cooper A, Drummond AJ (2005) Time dependency of molecular rate estimates and systematic overestimation of recent divergence times. Molecular Biology and Evolution 22: 1561–1568. 65. Pulquerio MJF, Nichols RA (2006) Dates from the molecular clock: how wrong can we be? Trends in Ecology and Evolution 22: 180–184. 66. Katzourakis A, Tristem M, Pybus OG, Gifford RJ (2007) Discovery and analysis of the first endogenous lentivirus. Proceedings of the National Academy of Sciences, USA 104: 6261–6265. 67. Bradley RS (1999) Paleoclimatology: reconstructing climates of the Quaternary. San Diego: Academic Press. 613 p. 68. Cronin TM (1999) Principles of Paleoclimatology. New York: Columbia University Press. 592 p. 69. Richerson PJ, Boyd RB, Bettinger RL (2001) Was agriculture impossible during the Pleistocene but mandatory during the Holocene? A climate change hypothesis. American Antiquity 66: 387–411. 70. Anderson PK, Cunningham AA, Patel NG, Morales FJ, Epstein PR, et al. (2004) Emerging infectious diseases of plants: pathogen pollution, climate change and agrotechnology drivers. Trends in Ecology and Evolution 19: 535–544. 71. Bawden FC (1955) The spread and control of plant virus diseases. Annals of Applied Biology 42: 140–147. 72. Kennedy JS, Day MF, Eastop VF (1962) A conspectus of aphids as vectors of plant viruses. London: Commonwealth Institute of Entomology. 114 p. 73. Blackman RL, Eastop VF (2000) Aphids on the worlds crops, an identification and information guide. London: Natural History Museum. 466 p. 74. Von Dohlen CD, Moran (2000) Molecular data support a rapid radiation of aphids in the Cretaceous and multiple origins of host alternation. Biological Journal of the Linnean Society 71: 689–717. 75. Von Dohlen CD, Rowe CA, Heie OE (2006) A test of morphological hypotheses for tribal and subtribal relationships of Aphidinae (Insecta: Hemiptera: Aphididae) using DNA sequences. Molecular Phylogenetics and Evolution 38: 316–329. 76. Tan Z, Gibbs AJ, Tomitaka Y, Sanchez F, Ponz F, et al. (2005) Mutations in turnip mosaic virus genomes that have adapted to Raphanus sativus. Journal of General Virology 86: 501–510. 77. Wallis CM, Stone AL, Sherman DJ, Damsteegt VD, Gildow FE, et al. (2007) Adaptation of plum pox virus to a herbaceous host (Pisum sativum) following serial passages. Journal of General Virology 88: 2839–2845. PLoS ONE | www.plosone.org 11 June 2008 | Volume 3 | Issue 6 | e2523