title: Molecular evolution of the period gene in Drosophila athabasca.
abstract: We measured nucleotide variability within and between the three semispecies of the Drosophila athabasca complex, at the period (per) gene by using a polymerase chain reaction-based four-cutter restriction-enzyme analysis. The levels of polymorphism varied considerably between the three semispecies. Our results for per, combined with previous data for X-linked allozymes, suggest that the X chromosome in the western-northern semispecies is less variable than expected under an equilibrium-neutral model. Both the pattern of divergence between the semispecies and a cladistic clustering of per haplotypes support the previously hypothesized grouping of eastern A and eastern B as the two most recently diverged semispecies. A 21-bp in-frame segment in the region of per which shares sequence similarity with the neuronal development gene single minded is deleted in all eastern A and eastern B flies examined but is present in all of the western-northern flies and all other published per sequences. Despite these hints that there may be significant differences at the per gene between the semispecies, especially the western-northern group versus the two eastern groups, there is no compelling evidence that per is involved in the mating song differences between the semispecies.
authors.affiliation: Section of Genetics and Development, Cornell University, Ithaca, New York 14853.
authors.forename: M J
authors.initials: MJ
authors.lastname: Ford
authors.forename: C K
authors.initials: CK
authors.lastname: Yoon
authors.forename: C F
authors.initials: CF
authors.lastname: Aquadro
mesh_terms: D000818:Animals; D001483:Base Sequence; D002170:Canada; D004330:Drosophila / Q000145:classification / Q000235:genetics*; D029721:Drosophila Proteins; D005260:Female; D005787:Gene Frequency; D017344:Genes, Insect; D008297:Male; D008969:Molecular Sequence Data; D009687:Nuclear Proteins / Q000235:genetics*; D056950:Period Circadian Proteins; D010802:Phylogeny; D011110:Polymorphism, Genetic; D012098:Reproduction; D016415:Sequence Alignment; D012689:Sequence Homology, Nucleic Acid; D013045:Species Specificity
chemical_list: D029721:Drosophila Proteins; D009687:Nuclear Proteins; C539040:PER protein, Drosophila; D056950:Period Circadian Proteins