title: Polymorphism patterns in two tightly linked developmental genes, Idgf1 and Idgf3, of Drosophila melanogaster.
abstract: A new developmental gene family, recently identified in D. melanogaster, has been called imaginal disc growth factors (IDGF) because the proteins promote growth of cell lineages derived from imaginal discs. These are the first genes reported that encode polypeptide factors with mitotic activity in invertebrates. Characteristics such as similar arrangement of introns and exons, small size, and different cytological localization make this family an excellent candidate for evolutionary studies. We focus on the loci Idgf1 and Idgf3, two genes that possess the most distinctive features. We examine the pattern of intra- and interspecific nucleotide variation in the sequences from 20 isogenic lines of D. melanogaster and sequences from D. simulans and D. yakuba. While MK, HKA, and Tajima's tests of neutrality fail to reject a neutral model of molecular evolution, Fu and Li's test with outgroup and McDonald's test suggest that balancing selection is modulating the evolution of the Idgf1 locus. The rate of recombination between the two loci is high enough to uncouple any linkage disequilibrium arising between Idgf1 and Idgf3, despite their close physical proximity.
authors.affiliation: Department of Ecology and Evolutionary Biology, University of California, Irvine, California 92697-2525, USA.
authors.forename: Martina
authors.initials: M
authors.lastname: Zurovcová
authors.forename: Francisco J
authors.initials: FJ
authors.lastname: Ayala
mesh_terms: D000818:Animals; D001483:Base Sequence; D004247:DNA; D029721:Drosophila Proteins / Q000737:chemistry / Q000235:genetics*; D004331:Drosophila melanogaster / Q000235:genetics*; D018507:Gene Expression Regulation, Developmental; D006023:Glycoproteins / Q000737:chemistry / Q000235:genetics*; D036341:Intercellular Signaling Peptides and Proteins; D015810:Linkage Disequilibrium; D008969:Molecular Sequence Data; D016133:Polymerase Chain Reaction; D011110:Polymorphism, Genetic; D011995:Recombination, Genetic; D012689:Sequence Homology, Nucleic Acid
chemical_list: D029721:Drosophila Proteins; D006023:Glycoproteins; D036341:Intercellular Signaling Peptides and Proteins; C472406:imaginal disc growth factor 1, Drosophila; C472407:imaginal disc growth factor 3, Drosophila; D004247:DNA