title: A Natural Population Derived from Species Hybridizationin the Drosophila ananassae Species Complexon Penang Island, Malaysia.
abstract: We surveyed natural population of the Drosophila ananassae species complex on Penang Island, Malaysia. Analyses of phenotypic traits, chromosome arrangements, molecular markers, and reproductive isolation suggest the existence of two species: D. ananassae and D. cf. parapallidosa. Molecular marker analysis indicates that D. cf. parapallidosa carries chromosome Y and 4 introgressions from D. ananassae. Thus, D. cf. parapallidosa seems to be a hybrid descendant that recently originated from a natural D. parapallidosa♀× D. ananassae♂ cross. Furthermore, D. cf. parapallidosa behaves differently from authentic D. parapallidosa with respect to its reproductive isolation from D. ananassae. Premating isolation is usually seen in only the D. ananassae♀× D. parapallidosa♂ cross, but we observed it in crosses of both directions between D. ananassae and D. cf. parapallidosa. In addition, hybrid males from the D. ananassae♀× D. parapallidosa♂ cross are usually sterile, but they were fertile when D. ananassae♀ were mated with D. cf. parapallidosa ♂. We attempted an artificial reconstruction of the hybrid species to simulate the evolutionary process(es) that produced D. cf. parapallidosa. This is a rare case of natural hybrid population in Drosophila and may be a useful system for elucidating speciation with gene flow.
authors.affiliation: 1 Faculty of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Ibaraki 305-8572, Japan.
authors.forename: Kyoichi
authors.initials: K
authors.lastname: Sawamura
authors.affiliation: 2 School of Medicine, Kyorin University, Mitaka, Tokyo 181-8611, Japan.
authors.forename: Hajime
authors.initials: H
authors.lastname: Sato
authors.affiliation: 3 Urban Entomology Laboratory, Vector Control Research Unit, School of Biological Sciences,Universiti Sains Malaysia, Minden 11800, Penang, Malaysia.
authors.forename: Chow-Yang
authors.initials: CY
authors.lastname: Lee
authors.affiliation: 3 Urban Entomology Laboratory, Vector Control Research Unit, School of Biological Sciences,Universiti Sains Malaysia, Minden 11800, Penang, Malaysia.|4 Department of Biology, Keio University, Yokohama, Kanagawa 223-8521, Japan.
authors.forename: Yoshitaka
authors.initials: Y
authors.lastname: Kamimura
authors.affiliation: 2 School of Medicine, Kyorin University, Mitaka, Tokyo 181-8611, Japan.
authors.forename: Muneo
authors.initials: M
authors.lastname: Matsuda
mesh_terms: D000818:Animals; D004330:Drosophila / Q000033:anatomy & histology / Q000145:classification / Q000235:genetics*; D005260:Female; D006824:Hybridization, Genetic; D008296:Malaysia; D008297:Male; D013045:Species Specificity
keywords: Drosophila ananassae; Drosophila parapallidosa; Penang Island; hybrid speciation; interspecific introgression