title: A karyotype study on the Drosophila robusta species-group (Diptera: Drosophilidae).
abstract: The karyotypes of the Drosophila robusta species-group, especially its species-subgroup okadai, were studied by using brain cell-Giemsa staining method. Drosophila gani possessed a diploid number of 12 chromosomes, comprising 4 pairs of metacentric, 2 pairs of acrocentric chromosomes, and both D. okadai and D. neokadai did 2n = 12, with 3 pairs of metacentrics, 2 pairs of acrocentrics and 1 pair of microchromosomes. The okadai subgroup characteristically retained a middle-sized acrocentric X chromosome, which implies that this subgroup may occupy an ancestral position for the robusta group.
authors.affiliation: Biological Laboratory, Sapporo College, Hokkaido University of Education, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Watabe
authors.forename: J
authors.initials: J
authors.lastname: Park
authors.forename: T
authors.initials: T
authors.lastname: Aotsuka
mesh_terms: D000818:Animals; D002874:Chromosome Mapping / Q000662:veterinary*; D004330:Drosophila / Q000235:genetics*; D007621:Karyotyping; D010802:Phylogeny