title: Local enrichment with homopolymeric (dA/dT) DNA in genomes of some lower dipterans and Drosophila melanogaster.
abstract: An investigation into the chromosomal localization of homopolymeric dA/dT was carried out with species of the genera Rhynchosciara, Chironomus, Drosophila and several other taxa. In situ hybridisation probing mitotic and polytene chromosomes with RNA homopolymers was performed, followed by immunological detection of the DNA/RNA hybrid. Use of this method allowed us to assess specific regions of some dipteran genomes, where the signal was generally, but not always, located in heterochromatic regions. Human and Drosophila chromosome regions known to contain dA/dT runs of up to 153 bp were devoid of consistent labelling. The stability of the rA/dT hybrid formed in situ was in agreement with the T(m) for long rA/dT hybrid complexes, suggesting that the method used in this work is able to identify unusually long homopolymeric dA/dT tracts.
authors.affiliation: Departamento de Biologia, Instituto de Biociências, Universidade de São Paulo, Rua do Matão 277, Cidade Universitária, Brazil CEP 05508-900.
authors.forename: Ann Jacob
authors.initials: AJ
authors.lastname: Stocker
authors.forename: Eduardo
authors.initials: E
authors.lastname: Gorab
mesh_terms: D000818:Animals; D002875:Chromosomes / Q000648:ultrastructure; D004247:DNA / Q000737:chemistry*; D004175:Diptera; D004331:Drosophila melanogaster / Q000235:genetics*; D016678:Genome; D006570:Heterochromatin / Q000648:ultrastructure; D006801:Humans; D017403:In Situ Hybridization; D007814:Larva / Q000378:metabolism; D008297:Male; D008938:Mitosis; D013045:Species Specificity
chemical_list: D006570:Heterochromatin; D004247:DNA