RESUMO
Sexually dimorphic characters have two-fold complexities in pattern formation as they have to get input from both somatic sex determination as well as the positional determining regulators. Sex comb development in Drosophila requires functions of the somatic sex-determining gene doublesex and the homeotic gene Sex combs reduced. Attempts have not been made to decipher the role of dsx in imparting sexually dimorphic expression of SCR and the differential function of sex-specific variants of dsx products in sex comb development. Our results in this study indicate that male-like pattern of SCR expression is independent of dsx function, and dsx F must be responsible for bringing about dimorphism in SCR expression, whereas dsx M function is required with Scr for the morphogenesis of sex comb.
Assuntos
Proteínas de Ligação a DNA/genética , Proteínas de Drosophila/genética , Drosophila melanogaster/genética , Morfogênese/genética , Fatores de Transcrição/genética , Animais , Evolução Biológica , Padronização Corporal/genética , Proteínas de Ligação a DNA/biossíntese , Proteínas de Drosophila/biossíntese , Drosophila melanogaster/crescimento & desenvolvimento , Feminino , Regulação da Expressão Gênica no Desenvolvimento , Masculino , RNA/biossíntese , Caracteres Sexuais , Fatores de Transcrição/biossínteseRESUMO
Sex comb is a recently evolved male specific character confined to the Sophophoran group of Drosophila. Such innovations in phenotypes as Waddington proposed, are, outcome of "canalization" in developmental pathways that occur due to mutations creating "choice points" in genetic regulatory pathways. Our interest in the present study is to understand the shifts in genetic network, which has lead to the origin of sex comb from the basic bristle pattern that is seen in rest of the members of Drosophilidae. Here we have made a comparative analysis of expression of some of the key regulators of sex comb morphogenesis, between D. melanogaster and a group of selected species, which primitively lack sex comb. Sex combs reduced (Scr), dachshund (dac), and bric-a-brac (bab) gene expression were studied. We show that, primitive bristle pattern is marked by a strikingly down regulated expression of Sex combs reduced in the first tarsal segment of the prothoracic leg discs of male flies. Further a remarkable change with respect to Dachshund, an activator of sex combs reduced gene in the sex comb regulatory pathway, is seen. This is attributed to changes in DAC protein that might have taken place between the two groups of species. bric-a-brac does not reveal any significant expression modulation between the sex comb bearing and the primitive patterned species. Earlier works had shown that within the Sophophoran group, dynamic changes in SCR expression is responsible for the diversity seen in sex comb morphology, where as no such variation is witnessed with respect to DAC expression. Our findings have demonstrated that the scenario is different between the group primitively lacking sex comb and D. melanogaster wherein an obvious change in the protein has taken place. genesis 51:97-109, 2013, 2013. © 2012 Wiley Periodicals, Inc.
Assuntos
Proteínas de Drosophila/genética , Drosophila melanogaster/anatomia & histologia , Caracteres Sexuais , Fatores de Transcrição/genética , Sequência de Aminoácidos , Animais , Evolução Biológica , Sequência Conservada , Proteínas de Ligação a DNA/genética , Proteínas de Drosophila/metabolismo , Drosophila melanogaster/genética , Regulação da Expressão Gênica no Desenvolvimento , Masculino , Dados de Sequência Molecular , Proteínas Nucleares , Especificidade da EspécieAssuntos
Envelhecimento/genética , Encéfalo/metabolismo , Proteínas de Ligação a DNA/metabolismo , Drosophila melanogaster/genética , Elementos Facilitadores Genéticos/genética , Regulação da Expressão Gênica no Desenvolvimento , Genes Reporter/genética , Proteínas de Saccharomyces cerevisiae/metabolismo , Fatores de Transcrição/metabolismo , Animais , Encéfalo/citologia , Drosophila melanogaster/citologia , Drosophila melanogaster/crescimento & desenvolvimento , Esôfago/inervação , Gânglios dos Invertebrados/citologia , Gânglios dos Invertebrados/metabolismo , Larva/citologia , Larva/metabolismo , Corpos Pedunculados/citologia , Corpos Pedunculados/metabolismo , Neuroglia/citologia , Neuroglia/metabolismo , Lobo Óptico de Animais não Mamíferos/citologia , Lobo Óptico de Animais não Mamíferos/metabolismo , Especificidade de Órgãos/genéticaAssuntos
Drosophila melanogaster/genética , Elementos Facilitadores Genéticos/genética , Regulação da Expressão Gênica no Desenvolvimento , Fatores de Transcrição/metabolismo , Animais , Animais Geneticamente Modificados , Encéfalo/anatomia & histologia , Encéfalo/fisiologia , Proteínas de Drosophila/genética , Proteínas de Drosophila/metabolismo , Drosophila melanogaster/crescimento & desenvolvimento , Genes Reporter/genética , Técnicas Genéticas , Histocitoquímica , Larva/citologia , Larva/fisiologia , Metamorfose Biológica/fisiologia , Fatores de Transcrição/genéticaRESUMO
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.
Assuntos
Cromossomos , Drosophila/genética , Animais , Bandeamento Cromossômico , Feminino , Masculino , Glândulas Salivares/ultraestrutura , Especificidade da EspécieRESUMO
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.
Assuntos
Drosophila/genética , Variação Genética , Filogenia , Alelos , Animais , Eletroforese em Gel de Poliacrilamida , Frequência do Gene , Índia , Terminologia como AssuntoRESUMO
Three paracentric inversions constitute the polymorphic system in Drosophila sulfurigaster neonasuta. Of these, two linked inversions, namely 2LA and 2RA, exhibit linkage disequilibrium, and the overall pattern of polymorphism is flexible.
Assuntos
Inversão Cromossômica , Drosophila/genética , Desequilíbrio de Ligação , Polimorfismo Genético , AnimaisRESUMO
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.
