title: Origin and evolution of a chimeric fusion gene in Drosophila subobscura, D. madeirensis and D. guanche.
abstract: An understanding of the mutational and evolutionary mechanisms underlying the emergence of novel genes is critical to studies of phenotypic and genomic evolution. Here we describe a new example of a recently formed chimeric fusion gene that occurs in Drosophila guanche, D. madeirensis, and D. subobscura. This new gene, which we name Adh-Twain, resulted from an Adh mRNA that retrotransposed into the Gapdh-like gene, CG9010. Adh-Twain is transcribed; its 5' promoters and transcription patterns appear similar to those of CG9010. Population genetic and phylogenetic analyses suggest that the amino acid sequence of Adh-Twain evolved rapidly via directional selection shortly after it arose. Its more recent history, however, is characterized by slower evolution consistent with increasing functional constraints. We present a model for the origin of this new gene and discuss genetic and evolutionary factors affecting the evolution of new genes and functions.
authors.affiliation: Center for Population Biology, University of California, Davis, 95616, USA. cdjones@email.unc.edu
authors.forename: Corbin D
authors.initials: CD
authors.lastname: Jones
authors.forename: Andrew W
authors.initials: AW
authors.lastname: Custer
authors.forename: David J
authors.initials: DJ
authors.lastname: Begun
mesh_terms: D020121:5' Untranslated Regions; D000426:Alcohol Dehydrogenase / Q000235:genetics*; D000818:Animals; D001483:Base Sequence; D004330:Drosophila / Q000235:genetics*; D019143:Evolution, Molecular; D008969:Molecular Sequence Data; D050506:Mutant Chimeric Proteins / Q000235:genetics*; D011110:Polymorphism, Genetic; D011401:Promoter Regions, Genetic; D011544:Pseudogenes
chemical_list: D020121:5' Untranslated Regions; D050506:Mutant Chimeric Proteins; D000426:Alcohol Dehydrogenase