title: Evidence of extensive genetic exchange in the rp49 region among polymorphic chromosome inversions in Drosophila subobscura.
abstract: Restriction map variation in 107 lines extracted from two natural populations of Drosophila subobscura was investigated with seven four-nucleotide-recognizing enzymes in a 1.6-kb region including the rp49 gene, that is located very close to the proximal breakpoint of inversion O3. Fourteen restriction site and 8 length polymorphisms, resulting in 73 haplotypes, have been identified. Estimated heterozygosity per nucleotide, pi = 0.0045, is comparable to the average nucleotide variation observed in Drosophila melanogaster. Because of the location of the rp49 region in D. subobscura, variation in three different gene arrangements-Ost, O3 + 4 and O3 + 4 + 8-has been compared. Out of 14 restriction site polymorphisms, 3 are shared by Ost, O3 + 4 and O3 + 4 + 8, and 3 additional ones are shared by Ost and O3 + 4, evidencing extensive genetic exchange among these polymorphic inversions. In agreement with previous data, the higher level of variation of O3 + 4 (as measured by haplotype diversity and nucleotide variation) suggests that O3 + 4 may be ancestral in relationship to extant gene arrangements.
authors.affiliation: Departament de Genètica, Facultat de Biologia, Universitat de Barcelona, Spain.
authors.forename: J
authors.initials: J
authors.lastname: Rozas
authors.forename: M
authors.initials: M
authors.lastname: Aguadé
mesh_terms: D000818:Animals; D001483:Base Sequence; D007446:Chromosome Inversion; D003433:Crosses, Genetic; D004330:Drosophila / Q000235:genetics*; D004331:Drosophila melanogaster / Q000235:genetics; D005260:Female; D005796:Genes; D014644:Genetic Variation; D006239:Haplotypes; D006579:Heterozygote; D008297:Male; D008969:Molecular Sequence Data; D011110:Polymorphism, Genetic; D011995:Recombination, Genetic; D015183:Restriction Mapping