and chromosome 1 had occurred in the common stem species of pufferfish and stickleback. Found at: doi:10.1371/journal.pgen.1000025.s002 (0.05 MB DOC) Table S1 Dogfish Primers. Primers employed to amplify and analyze the expression of Runt genes in dogfish. PA: Primary amplification, RA: Reamplification. Found at: doi:10.1371/journal.pgen.1000025.s003 (0.08 MB DOC) Table S2 Hagfish Primers. Primers employed to detect Runt genes and analyze Runt gene expression in hagfish. PA: Primary amplification, RA: Reamplification. Found at: doi:10.1371/journal.pgen.1000025.s004 (0.07 MB DOC) Table S3 Amphioxus Primers. Primers employed to analyze Sox9, Hedgehog and Runt genes in lancelets. Found at: doi:10.1371/journal.pgen.1000025.s005 (0.08 MB DOC) References 1. Hall BK (2005) Bones and Cartilage, Developmental and Evolutionary Skeletal Biology. London: Elsevier Academic Press. pp 760. 2. 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Hall BK (1999) The neural crest in development and evolution. New York: Springer. pp 314. 43. Meulemans D, Bronner-Fraser M (2005) Central role of gene cooption in neural crest evolution. J Exp Zoolog B Mol Dev Evol 304: 298–303. PLoS Genetics | www.plosgenetics.org 12 March 2008 | Volume 4 | Issue 3 | e1000025