title: Ultrastructure of regions containing homologous loci in polytene chromosomes of Drosophila melanogaster and Drosophila subobscura.
abstract: We have used a new approach involving in situ hybridisation and electron microscopy to establish ultrastructural homologies between polytene chromosome regions of Drosophila melanogaster and Drosophila subobscura. Twelve probes were chosen to cover all the chromosomal elements: the myospheroid gene, the collagen type IV gene, the collagen-like gene, the w26 homeobox gene, the beta3 tubulin gene, the kinesin heavy chain gene, the tryptophan hydrolase gene, the Hsp82, Hsp22-26 and Hsp23-28, Hsp68, Hsp70 genes and the beta unit of the F0-F1 ATPase gene. Most of these loci were previously undescribed in D. subobscura and imprecisely located in D. melanogaster. We have demonstrated here, by an ultrastructural analysis of each chromosomal region, that homologous genetic loci tend to show a similar ultrastructure in the two species. With a few exceptions, the structural homology extends to the chromosomal regions surrounding the loci. In some cases, however, no structurally recognisable homology can be seen either in the locus or in its flanking regions.
authors.affiliation: Departament de Genética, Universitat de València, c/Dr. Moliner 50, E-46100-Burjassot, València, Spain. Ibo.Galindo@uv.es
authors.forename: J B
authors.initials: JB
authors.lastname: Cuenca
authors.forename: M I
authors.initials: MI
authors.lastname: Galindo
authors.forename: A O
authors.initials: AO
authors.lastname: Saura
authors.forename: V
authors.initials: V
authors.lastname: Sorsa
authors.forename: R
authors.initials: R
authors.lastname: de Frutos
mesh_terms: D000818:Animals; D002871:Chromosome Banding; D002875:Chromosomes / Q000648:ultrastructure*; D003094:Collagen / Q000235:genetics; D015342:DNA Probes; D029721:Drosophila Proteins; D004331:Drosophila melanogaster / Q000235:genetics* / Q000648:ultrastructure; D017344:Genes, Insect; D050886:HSP20 Heat-Shock Proteins; D050890:HSP30 Heat-Shock Proteins; D018840:HSP70 Heat-Shock Proteins / Q000235:genetics; D006360:Heat-Shock Proteins / Q000235:genetics; D039001:Integrin alpha Chains; D016023:Integrins / Q000235:genetics; D016547:Kinesins / Q000235:genetics; D008565:Membrane Proteins / Q000235:genetics; D009124:Muscle Proteins; D006180:Proton-Translocating ATPases / Q000235:genetics; D012689:Sequence Homology, Nucleic Acid; D014365:Tryptophan Hydroxylase / Q000235:genetics; D014404:Tubulin / Q000235:genetics
chemical_list: D015342:DNA Probes; D029721:Drosophila Proteins; D050886:HSP20 Heat-Shock Proteins; D050890:HSP30 Heat-Shock Proteins; D018840:HSP70 Heat-Shock Proteins; D006360:Heat-Shock Proteins; C490752:Hsp22 protein, Drosophila; C105998:Hsp23 protein, Drosophila; C087442:Hsp26 protein, Drosophila; C490785:Hsp68 protein, Drosophila; C089272:Hsp83 protein, Drosophila; C490753:HspB8 protein, rat; D039001:Integrin alpha Chains; D016023:Integrins; D008565:Membrane Proteins; D009124:Muscle Proteins; D014404:Tubulin; C082188:if protein, Drosophila; C087458:Hspb6 protein, rat; D003094:Collagen; D014365:Tryptophan Hydroxylase; D006180:Proton-Translocating ATPases; D016547:Kinesins