title: The early expansion and evolutionary dynamics of POU class genes.
abstract: The POU genes represent a diverse class of animal-specific transcription factors that play important roles in neurogenesis, pluripotency, and cell-type specification. Although previous attempts have been made to reconstruct the evolution of the POU class, these studies have been limited by a small number of representative taxa, and a lack of sequences from basally branching organisms. In this study, we performed comparative analyses on available genomes and sequences recovered through "gene fishing" to better resolve the topology of the POU gene tree. We then used ancestral state reconstruction to map the most likely changes in amino acid evolution for the conserved domains. Our work suggests that four of the six POU families evolved before the last common ancestor of living animals-doubling previous estimates-and were followed by extensive clade-specific gene loss. Amino acid changes are distributed unequally across the gene tree, consistent with a neofunctionalization model of protein evolution. We consider our results in the context of early animal evolution, and the role of POU5 genes in maintaining stem cell pluripotency.
authors.affiliation: Department of Ecology and Evolution, University of California, Los Angeles.
authors.forename: David A
authors.initials: DA
authors.lastname: Gold
authors.affiliation: Department of Ecology and Evolution, University of California, Los Angeles.
authors.forename: Ruth D
authors.initials: RD
authors.lastname: Gates
authors.affiliation: Department of Ecology and Evolution, University of California, Los Angeles djacobs@ucla.edu.
authors.forename: David K
authors.initials: DK
authors.lastname: Jacobs
mesh_terms: D000818:Animals; D001499:Bayes Theorem; D016384:Consensus Sequence; D019143:Evolution, Molecular; D016013:Likelihood Functions; D008958:Models, Molecular; D008969:Molecular Sequence Data; D050809:POU Domain Factors / Q000737:chemistry / Q000235:genetics*; D010802:Phylogeny; D017434:Protein Structure, Tertiary
chemical_list: D050809:POU Domain Factors
keywords: EvoDevo; Metazoa; POU; gene duplication; homeobox; stem cells