Montium Subgroup Research Articles

The Drosophila montium subgroup species. Phylogenetic relationships based on mitochondrial DNA analysis.

Mitochondrial DNA (mtDNA) restriction site maps for three Drosophila montium subgroup species of the melanogaster species group, inhabiting Indian and Afrotropical montium subgroup territories, were established. Taking into account previous mtDNA data concerning six oriental montium species, a phylogeny was established using distance-matrix and parsimony methods. Both genetic diversity and mtDNA size variations were found to be very narrow, suggesting close phylogenetic relationships among all montium species studied. The phylogenetic trees that were constructed revealed three main lineages for the montium subgroup species studied: one consisting of the Afrotropical species Drosophila seguyi, which is placed distantly from the other species, one comprising the north-oriental (Palearctic) species, and one comprising the southwestern (south-oriental, Australasian, Indian, and Afrotropical) species. The combination of the mtDNA data presented here with data from other species belonging to the melanogaster and obscura subgroups revealed two major clusters: melanogaster and obscura. The melanogaster cluster is further divided into two compact lineages, comprising the montium subgroup species and the melanogaster complex species; the species of the other complex of the melanogaster subgroup, yakuba, disperse among the obscura species. The above grouping is in agreement with the mtDNA size variations of the species. Overall, among all subgroups studied, the species of the montium subgroup seem to be the most closely related.

The heat shock genes in the Drosophila montium subgroup: chromosomal localization and evolutionary implications.

The hsp70, hsp83, hsromega, and the small heat shock protein genes were mapped on the polytene chromosomes of six species, representative of the geographical distribution of the Drosophila montium subgroup of the melanogaster species group. In addition, based on hybridization conditions, the putative locus of the hsp68 gene is given. In contrast to the situation in the melanogaster subgroup species, the hsp70 locus is single in the montium species. The hsp83, hsromega and the small hsp loci are also single in the montium genomes studied here, a common feature of all Drosophila species. Among the hsp genes studied, the small hsp genes and the hsromega-homologous sequences exhibit a higher degree of divergence between the melanogaster and the montium subgroups. Our results support the idea that the montium subgroup species has a genome organization closer to that of the common ancestor compared with the melanogaster subgroup species.

The Afrotropical Drosophila montium subgroup: Balbiani ring 1, polytene chromosomes, and heat shock response of Drosophila vulcana.

A detailed photographic map of the salivary gland polytene chromosomes of Drosophila vulcana, an Afrotropical species of the montium subgroup of the melanogaster group, is presented, along with chromosomal rearrangements, such as reverse tandem duplications and inversions, the well-formed Balbiani ring 1, and the most prominent puffs during normal larval and white prepupal development and after ecdysone treatment. In addition, the heat inducible protein and puffing pattern and the loci of the major heat shock genes, namely, hsp70, hsp83, the "small" hsps, and a putative hsp68, of this species were studied. In the light of the data revealed by the above studies, phylogenetic relationship among the montium subgroup species are attempted.

The ?-tubulin gene family evolution in the Drosophila montium subgroup of the melanogaster species group

The beta 1-, beta 2-, and beta 3-tubulin genes have been mapped by in situ hybridization on the polytene chromosomes of 11 selected species (15 strains) belonging to the Drosophila montium subgroup. Although the hybridization pattern among the strains of the same species does not differ, this pattern is significantly different among the species. The beta-tubulin genes in the montium subgroup seem to be organized in a cluster, or in a semicluster or are completely dispersed. The clustered arrangements is found in the North-Oriental sibling species D. auraria, D. triauraria, and D. quadraria. The semiclustered arrangement, wherein the beta 1 and beta 2 genes are located at the same locus while beta 3 is at a different one, appears in the South-Oriental species D. bicornuta, D. serrata, and D. birchii, as well as in the Afrotropical species D. diplacantha and D. seguyi. The complete separation of the genes is observed in the Indian species D. kikkawai and D. jambulina and in the Afrotropical species D. vulcana. Based on the above results, a possible mode of evolution of the beta-tubulin genes in the montium subgroup is attempted. In addition, phylogenetic relationships among the montium species are discussed.

Cytotaxonomic differentiation of the Afrotropical Drosophila montium subgroup: D. diplacantha and D. seguyi. The major role of reverse tandem duplications

Aiming to establish phylogenetic relationships among species of the montium subgroup, detailed polytene chromosome maps are given showing intraspecific polymorphism and ecdysone induced larval puffing pattern profiles of two Afrotropical members of this subgroup, Drosophila diplacantha and D. seguyi. Both species exhibit two unique characteristics that define the montium subgroup, namely, a large number of reverse tandem duplications and a progressive darkening of anterior spiracles of the late third instar larvae, which is accompanied by a definite temporal and spatial puffing pattern of the salivary gland chromosomes. In contrast with the well-formed Balbiani ring 1 (BR1) observed in Oriental and Indian montium species, BR1 exhibits a different developmental profile in D. diplacantha, while it is obscured in D. seguyi. Although phyletic comparisons of five species from five different complexes within the subgroup show some conservation in banding and puffing pattern homologies, an analysis to assign map sections by sequential rearrangements remains unresolved at this time. The evolution of the subgroup is discussed in relation with the sharing of reverse tandem duplications, especially those including the montium BRs.

Molecular phylogeny of Drosophila based on ribosomal RNA sequences

Nucleotide sequences of 72 species of Drosophilidae were determined for divergent D1 and D2 domains (representing 200 and 341 nucleotides respectively in D. melanogaster) of large ribosomal RNA, using the rRNA direct sequencing method. Molecular phylogenetic trees were reconstructed using both distance and parsimony methods and the robustness of the nodes was evaluated by the bootstrap procedure. The trees obtained by these methods revealed four main lineages or clades which do not correspond to the taxonomical hierarchy. In our results, the genus Chymomyza is associated with the subgenus Scaptodrosophila of the genus Drosophila and their cluster constitutes the most ancient clade. The two other clades are constituted of groups belonging to the subgenus Sophophora of the genus Drosophila: the so-called Neotropical clade including the willistoni and saltans groups and the obscura-melanogaster clade itself split into three lineages: (1) obscura group + ananassae subgroup, (2) montium subgroup, and (3) melanogaster + Oriental subgroups. The fourth clade, the Drosophila one, contains three lineages. D. polychaeta, D. iri, and D. fraburu are branched together and constitute the most ancient lineage; the second lineage includes the annulimana, bromeliae, dreyfusi, melanica, mesophragmatica, repleta, robusta, and virilis groups. The third lineage is composed of the immigrans and the cardini, funebris, guaramunu, guarani, histrio, pallidipennis, quinaria, and tripunctata groups. The genera Samoaia, Scaptomyza, and Zaprionus are branched within the Drosophila clade. Although these four clades appear regularly in almost all tree calculations, additional sequencing will be necessary to determine their precise relationships.

Drosophila watanabei, a new species of themontiumsubgroup of themelanogasterspecies group of the subgenusSophophora(Diptera: Drosophilidae)

Abstract Drosophila watanabei, sp. nov. is described and its relationship with other species within the montium subgroup is discussed.

The Chromosomes of Three Species of the Montium Subgroup of Drosophila

Chromosomes of Drosophila truncata, D. nagarholensis, and D. agumbensis of the montium subgroup were analyzed to record the divergence attained at the level of metaphase complement and the extent of inversion polymorphism. Results are presented in this article.

Molecular phylogeny of the subgenus Sophophora of Drosophila derived from large subunit of ribosomal RNA sequences

RNA sequencing has been used to assess the relationships among species of the subgenus Sophophora of the genus Drosophila. Two divergent domains, D1 and D2, of the large ribosomal RNA (28S), totalling 550 nucleotides have been sequenced using the rRNA direct sequencing method. A tree has been reconstructed from the neighbor-joining algorithm and the confidence intervals were evaluated by the bootstrap procedure. Results have shown that the branching of the willistoni and saltans groups of the subgenus Sophophora is very ancient and probably predates that of the subgenus Drosophila. The other groups and subgroups of Sophophora are clustered in three main lineages: 1) the melanogaster and oriental subgroups; 2) the montium subgroup; 3) the ananassae subgroup of the melanogaster group clustered with the fima and obscura groups. Thus, in comparison with our results, several taxa of various ranks appear paraphyletic (the genus Drosophila, the subgenus Sophophora and the melanogaster group). Our biochemical phylogeny is only in partial agreement with the pattern of Throckmorton's radiations as well as with classical taxonomy, both based on morphological data.

Distribution of hobo transposable elements in the genus Drosophila.

This study describes the distribution of hobo-hybridizing sequences in the genus Drosophila. Southern blot analysis of 134 species revealed that hobo sequences are limited to the melanogaster and montium subgroups of the melanogaster-species group. Of the hobo-bearing species, only D. melanogaster and two of its sibling species, D. simulans and D. mauritiana, were found to contain potentially complete hobo elements. The distribution of hobo sequences is one of the narrowest distributions thus far described for any Drosophila transposable element.

Biochemical phylogeny of seven Indian species of the montium subgroup of Drosophila

Seven species of the montium subgroup of Drosophila found in South India were analysed with polyacrylamide disc electrophoresis. Eleven loci coding for enzymes were surveyed. The genetic distances between species have been measured. The dendrogram revealed three clusters. The first cluster includes D. nagarholensis, D. agumbensis, D. jambulina and D. kikkawai; the second group consists of D. truncata and D. anomelani; while D. mysorensis was the only species of the third group.

Metaphase karyotype differentiation in eight species of the montium subgroup of Drosophila.

The metaphase karyotypes of eight species of the montium species subgroup of Drosophila are described, of which the information pertaining to six species is new to the literature. Each of these species studied was distinctly different from the others with respect to the metaphase chromosomes, this remarkable degree of differentiation being mainly due to the extensive variability of the 4th and of the Y chromosomes.

Distribution and conservation of the foldback transposable element inDrosophila

Foldback elements are a family of transposable elements described in Drosophila melanogaster. The members of this dispersed repetitive family have terminal inverted repeats that sometimes flank a central region. The inverted repeats of all the family members are homologous. The study of the distribution and conservation of the foldback elements in different Drosophila species shows that this distribution is different from that of the hybrid dysgenesis systems (PM and IR). Sequences homologous to foldback elements were observed by Southern blots and in situ hybridization in all species of the melanogaster subgroup and in some species of the montium and takahashii subgroups. The element was probably already present before the radiation of these subgroups. No evidence of horizontal transmission of the foldback element could be observed.

Evolutionary genetics of the Drosophila montium subgroup. I. Reproductive isolations and the phylogeny.

Seventeen species of the Drosophila montium subgroup, originated from the Southeast Asia, were genetically examined to clarify the phylogenetic relationships. Among 272 interspecific crosses, 61 combinations were successful in mating and 39 combinations produced hybrid flies. These results enabled us to classify the subgroup into three species complexes: the kikkawai complex (6 species), the jambulina complex (4 species) and the auraria complex (7 species), which were very similar to that obtained by the electrophoretic classification (Ohnishi and Watanabe, 1984). Asymmetrical mating preference between species was found in the present experiment. They were applied to estimate the relative age of species according to the hypothesis proposed by Watanabe and Kawanishi (1979). The evolving order was as follows: kikkawai, leontia, pennae, lini-like, lini, bocki in the kikkawai complex, punjabiensis, punjabiensis-like, jambulina, barbarae in the jambulina complex, and quadraria, yuwanensis, rufa, subauraria, biauraria, triauraria, auraria in the auraria complex. Hybrid flies, if produced, were mostly fertile or partially fertile in both sexes (32/39) within species complex crosses. Therefore premating isolation played a more important role than postmating isolation in speciation of the D. montium subgroup.

Chromosome inversion polymorphism in natural populations of Drosophila punjabiensis Parshad and Paika

Drosophila punjabiensis, a member of the montium subgroup of the melanogaster species group is a very common and widespread species of Drosophila in the Indian subcontinent. Analysis of different geographic populations of this species in India has revealed altogether nine paracentric inversions. The relationship between inversions and the different environmental conditions is discussed. The pattern of inversion polymorphism in D. punjabiensis and its sibling species, D. jambulina are compared.

Genetic analysis of color dimorphism in the Drosophila montium subgroup.

Four Drosophila species, D. baimaii, D. bicornuta, D, burlai and D, truncata, belonging to the montium species subgroup, were examined for the abdominal tergite coloration. Females show dimorphsim, light or dark, in coloration. In all species examined, the color dimorphism is regulated by two alleles of a single autosomal locus and the dark allele is dominant. Males of the first three species show monomorphic tergite coloration, either light or dark, while males of the fourth species, D. truncata, show the light/dark color dimorphism. Here again it is controlled by two alleles of a single autosomal gene and the dark allele is dominant.

Two new species of drosopiiila from India (Diptera : Drosopiiilidae)

Abstract Two new species, Drosophila brahmagirensis and D. bhagamandalensis, members of the montium subgroup of the melanogoster species-group collected from tropical rain forests of Western Ghats in Brahmagiri hills and Bhagamandala Ghats, Coorg District, Karnataka, India are described. The taxonomic status and relationships are discussed.

Drosophila madikerii, sp. nov. from Coorg District (Western Ghats) Karnataka, India (Diptera : Drosophilidae)

Abstract Drosophila madikerii, sp. no v., a member of the montium subgroup of the melanogaster group, collected from the tropical rain forests of Coorg District (Western Ghats) near Madikeri, is described. The taxonomic position and its affinities are discussed.

Pattern of chromosomal polymorphism in Drosophila jambulina Parshad and paika.

Drosophila jambulina is a new species belonging to the montium subgroup of the melanogaster species group of the subgenus Sophophora. It is one of the commonest and most widespread species in India. A map of its salivary gland chromosomes has been constructed and some identifiable landmarks in each arm of the chromosome are recognized. Analysis of population samples from eight different geographical localities has yielded five different autosomal inversions, all confined to the right arm of 3rd chromosome only. However, irradiation study has shown that the distribution of induced rearrangements is more or less at random throughout the chromosomes in this species.

Isozyme variation and phylogenetic relationships among six species of the montium subgroup of the Drosophila melanogaster species group

Isozyme variation and phylogenetic relationships among six species of the montium subgroup of the Drosophila melanogaster species group