title: Interspecific and intraspecific comparisons of the period locus in the Drosophila willistoni sibling species.
abstract: The period (per) locus has received much attention in molecular evolution studies because it is one of the best studied "behavioral genes" and because it offers insight into the evolution of repetitive sequences. We studied most of the coding region of per in Drosophila willistoni and confirmed previously observed patterns of conservation and divergence among distantly related species. Five regions are so highly diverged that they cannot be aligned, whereas a region encompassing the PAS domain is very conserved. Structural and nucleotide polymorphism patterns in the willistoni group are not the same as those observed in previously studied species. We sequenced the region homologous to the highly polymorphic threonine-glycine repeat of D. melanogaster in multiple strains of D. willistoni, as well as in other members of willistoni group, and found an unusual amount of conservation in this region. However, the next nonconserved region downstream in the sequence is quite variable and polymorphic for the number of repeated glycines. The glycine codon usage is significantly different in this glycine repeat as compared to other parts of the gene. We were able to plot the directionality of change in the glycine repeat region onto a phylogeny and find that the addition of glycines is the general trend with the diversification of the willistoni group.
authors.affiliation: Department of Biology, Yale University, USA. jennifer.gleason@st-andrews.ac.uk
authors.forename: J M
authors.initials: JM
authors.lastname: Gleason
authors.forename: J R
authors.initials: JR
authors.lastname: Powell
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D005075:Biological Evolution; D003062:Codon; D004330:Drosophila / Q000235:genetics*; D029721:Drosophila Proteins; D017344:Genes, Insect; D005998:Glycine; D008969:Molecular Sequence Data; D009687:Nuclear Proteins / Q000235:genetics*; D056950:Period Circadian Proteins; D011110:Polymorphism, Genetic; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D012689:Sequence Homology, Nucleic Acid; D013045:Species Specificity
chemical_list: D003062:Codon; D029721:Drosophila Proteins; D009687:Nuclear Proteins; C539040:PER protein, Drosophila; D056950:Period Circadian Proteins; D005998:Glycine