RESUMO
We expanded the view of Clock (Clk) and cycle (cyc) gene evolution in Diptera by studying the fruit fly Anastrepha fraterculus (Afra), a Brachycera. Despite the high conservation of clock genes amongst insect groups, striking structural and functional differences of some clocks have appeared throughout evolution. Clk and cyc nucleotide sequences and corresponding proteins were characterized, along with their mRNA expression data, to provide an evolutionary overview in the two major groups of Diptera: Lower Diptera and Higher Brachycera. We found that AfraCYC lacks the BMAL (Brain and muscle ARNT-like) C-terminus region (BCTR) domain and is constitutively expressed, suggesting that AfraCLK has the main transactivation function, which is corroborated by the presence of poly-Q repeats and an oscillatory pattern. Our analysis suggests that the loss of BCTR in CYC is not exclusive of drosophilids, as it also occurs in other Acalyptratae flies such as tephritids and drosophilids, however, but it is also present in some Calyptratae, such as Muscidae, Calliphoridae and Sarcophagidae. This indicates that BCTR is missing from CYC of all higher-level Brachycera and that it was lost during the evolution of Lower Brachycera. Thus, we can infer that CLK protein may play the main role in the CLK\CYC transcription complex in these flies, like in its Drosophila orthologues.
Assuntos
Fatores de Transcrição ARNTL/genética , Proteínas CLOCK/genética , Proteínas de Drosophila/genética , Drosophila/genética , Evolução Molecular , Tephritidae/genética , Sequência de Aminoácidos , Animais , Feminino , Componentes do Gene , Masculino , Dados de Sequência Molecular , Tephritidae/metabolismoRESUMO
The developmental cycles of five Brazilian populations of the Lutzomyia longipalpis Lutz & Neiva species complex (Diptera: Psychodidae) were compared under laboratory conditions. Three of the populations were derived from insects collected in allopatric sites at Natal (Rio Grande do Norte State), Jacobina (Bahia State) and Lapinha Cave (Minas Gerais State). The other two originated from Sobral (Ceará State), where the males of two sympatric species can be distinguished by the presence of one (1S) or two (2S) pairs of abdominal spots. The results of the present study clearly show that all three populations whose males produce C16 pheromones and use pulse-type copulation songs (Jacobina, Lapinha Cave and Sobral 1S) are more easily adapted to the colonization conditions used in our laboratory, producing larger egg batches, with higher survival and an overall faster developmental cycle. This contrasts with populations producing C20 male pheromones and using burst-type copulation songs (Natal and Sobral 2S) that produce smaller egg batches, have higher oviposition mortality and a slower rate of development under identical laboratory conditions. In conclusion, these phenological differences are a further indication of the differentiation of the siblings within the Lu. longipalpis species complex.
Assuntos
Estágios do Ciclo de Vida , Psychodidae/fisiologia , Animais , Brasil , Feminino , Geografia , Humanos , Insetos Vetores , Masculino , Oviposição , Feromônios/fisiologia , Febre por Flebótomos/parasitologia , Polimorfismo Genético , Psychodidae/genética , Psychodidae/crescimento & desenvolvimento , Reprodução/fisiologia , Especificidade da EspécieRESUMO
The sandfly Lutzomyia longipalpis s.l. is the main vector of American Visceral Leishmaniasis. L. longipalpis s.l. is a species complex but until recently the existence of cryptic sibling species among Brazilian populations was a controversial issue. A fragment of paralytic (para), a voltage dependent sodium channel gene associated with insecticide resistance and courtship song production in Drosophila, was isolated and used as a molecular marker to study the divergence between two sympatric siblings of the L. longipalpis complex from Sobral, Brazil. The results revealed para as the first single locus DNA marker presenting fixed differences between the two species in this locality. In addition, two low frequency amino-acid changes in an otherwise very conserved region of the channel were observed, raising the possibility that it might be associated with incipient resistance in this vector. To the best of our knowledge, the present study represents the first population genetics analysis of insecticide resistance genes in this important leishmaniasis vector.
Assuntos
Comunicação Animal , Corte , Genes de Insetos/genética , Insetos Vetores/genética , Resistência a Inseticidas/genética , Psychodidae/genética , Substituição de Aminoácidos/genética , Animais , Marcadores Genéticos , Insetos Vetores/classificação , Insetos Vetores/fisiologia , Leishmaniose/transmissão , Dados de Sequência Molecular , Reação em Cadeia da Polimerase , Psychodidae/classificação , Psychodidae/fisiologia , Canais de Sódio/genética , Especificidade da EspécieRESUMO
Lutzomyia longipalpis s.l. (Lutz & Neiva) (Diptera: Psychodidae) is the main vector of visceral leishmaniasis in Latin America. Differences in copulation songs, pheromones and molecular markers show that L. longipalpis is a species complex in Brazil. The patterns of activity of insect vectors are important in disease transmission. In addition, differences in activity rhythms have a potential role as a temporal reproductive isolation mechanism in closely related species. We compared the activity patterns of males and females of two sympatric species of the Longipalpis complex from Sobral (Ceará State, Brazil) in controlled laboratory conditions. We observed small but significant differences between the two species in the activity phase in both males and females.
Assuntos
Psychodidae/classificação , Psychodidae/fisiologia , Animais , Comportamento Animal , Brasil , Ritmo Circadiano/fisiologia , Feminino , Masculino , Atividade Motora/fisiologiaRESUMO
The constitutive ribosomal gene rp49 is frequently used as an endogenous control in Drosophila gene expression experiments. Using the degenerate primer PCR technique we have cloned a fragment homologous to this gene in Anopheles aquasalis Curry, a Neotropical vector of malaria. In addition, based on this first sequence, a new primer was designed, which allowed the isolation of fragments of rp49 in two other species, Aedes aegypti (Linnaeus) and Culex quinquefasciatus Say, suggesting that it could be used to clone fragments of this gene in a number of other mosquito species. Primers were also designed to specifically amplify rp49 cDNA fragments in An. aquasalis and Ae. aegypti, showing that rp49 could be used as a good constitutive control in gene expression studies of these and other vectorially important mosquito species.
Assuntos
Culicidae/genética , Proteínas de Drosophila/isolamento & purificação , Drosophila/genética , Insetos Vetores/genética , Proteínas Ribossômicas/isolamento & purificação , Aedes/genética , Animais , Anopheles/genética , Culex/genética , Primers do DNA/genética , DNA Complementar/genética , Proteínas de Drosophila/genética , Expressão Gênica , Reação em Cadeia da Polimerase , Proteínas Ribossômicas/genéticaRESUMO
The constitutive ribosomal gene rp49 is frequently used as an endogenous control in Drosophila gene expression experiments. Using the degenerate primer PCR technique we have cloned a fragment homologous to this gene in Anopheles aquasalis Curry, a Neotropical vector of malaria. In addition, based on this first sequence, a new primer was designed, which allowed the isolation of fragments of rp49 in two other species, Aedes aegypti (Linnaeus) and Culex quinquefasciatus Say, suggesting that it could be used to clone fragments of this gene in a number of other mosquito species. Primers were also designed to specifically amplify rp49 cDNA fragments in An. aquasalis and Ae. aegypti, showing that rp49 could be used as a good constitutive control in gene expression studies of these and other vectorially important mosquito species.
Assuntos
Animais , Aedes/genética , Anopheles/genética , Culex/genética , Proteínas de Drosophila/isolamento & purificação , Drosophila/genética , Insetos Vetores/genética , DNA Complementar/genética , Proteínas de Drosophila/genética , Expressão Gênica , Reação em Cadeia da PolimeraseRESUMO
Genes involved in the reproductive isolation are particularly useful as molecular markers in speciation studies. Lutzomyia longipalpis (Diptera: Psychodidae: Phlebotominae), a putative species complex, is a vector of visceral leishmaniasis in Latin America. We isolated from this species a fragment homologous to cacophony, a Drosophila gene that encodes features of the lovesong, an acoustic signal that is important in the sexual isolation of closely related species and known to vary considerably among L. longipalpis putative siblings species. Using an intron of the sandfly cacophony as a marker, we analyzed the molecular variation and sequence divergence among five populations of L. longipalpis from Brazil, three allopatric (Jacobina, Lapinha and Natal) and two putative sympatric sibling species from the locality of Sobral. A high level of polymorphism was found and analysis of the data indicates that very little gene flow is occurring among the populations of Jacobina, Lapinha, and Natal. A high level of differentiation was also observed between the two putative sympatric species of Sobral, one of which seems to be the same sibling species found in Natal, while the other is somewhat more related to Jacobina and Lapinha. However, the amount of estimated gene flow among the Sobral siblings is about seven times higher than the previously estimated for period, another lovesong gene, perhaps indicating that introgression might be affecting cacophony more than period. The results suggest that L. longipalpis is not a single species in Brazil, but it is yet not clear whether the different populations studied deserve species status rather than representing an incipient speciation process.
Assuntos
Proteínas de Drosophila/genética , Evolução Molecular , Variação Genética , Genética Populacional , Psychodidae/genética , Análise de Variância , Animais , Sequência de Bases , Brasil , Análise por Conglomerados , Primers do DNA , Geografia , Íntrons/genética , Dados de Sequência Molecular , Filogenia , Alinhamento de Sequência , Análise de Sequência de DNA , Especificidade da EspécieRESUMO
The molecular evolution of the clock gene period was studied in Phlebotomine sandflies (Diptera: Psychodidae). Comparison of the synonymous and nonsynonymous substitution rates between sandflies and Drosophila revealed a significantly higher evolutionary rate in the latter in three of the four regions analyzed. The differences in rate were higher in the sequences flanking the Thr-Gly repetitive domain, a region that has expanded in Drosophila but remained stable and short in sandflies, a result consistent with the coevolutionary scenario proposed for this region of the gene. An initial phylogenetic analysis including eight neotropical sandfly species and one from the Old World was also carried out. The results showed that only the subgenus Nyssomyia is well supported by distance (neighbor-joining) and maximum parsimony analysis. The grouping of the other species from the subgenus Lutzomyia and Migonei group shows very low bootstrap values and is not entirely consistent with classical morphological systematics of the genus Lutzomyia.
Assuntos
Evolução Molecular , Genes de Insetos , Proteínas Nucleares/genética , Psychodidae/genética , Sequência de Aminoácidos , Animais , Sequência de Bases , Relógios Biológicos/genética , DNA/genética , Proteínas de Drosophila , Dados de Sequência Molecular , Proteínas Circadianas Period , Filogenia , Homologia de Sequência de Aminoácidos , Homologia de Sequência do Ácido NucleicoRESUMO
Lutzomyia longipalpis (Diptera: Psychodidae: Phlebotominae), the main vector of visceral leishmaniasis in the Americas, is a putative species complex. Molecular polymorphism was characterized in a 266 bp fragment of L. longipalpis homologous to period, a 'speciation gene' from Drosophila. Samples from the Brazilian localities of Jacobina (BA), Lapinha (MG) and Natal (RN) were analysed and the data indicate that the three populations are highly differentiated, with a very low level of gene flow between them. These results are in agreement with published pheromone and copulation song studies that suggest the existence of a sibling species complex in Brazil.
Assuntos
Proteínas Nucleares/genética , Psychodidae/genética , Sequência de Aminoácidos , Animais , Sequência de Bases , Brasil , DNA/química , DNA/genética , Proteínas de Drosophila , Feminino , Variação Genética/genética , Masculino , Dados de Sequência Molecular , Proteínas Nucleares/química , Proteínas Circadianas Period , Filogenia , Reação em Cadeia da Polimerase , Análise de Sequência de DNA , Homologia de Sequência do Ácido NucleicoRESUMO
We present the results of recording male courtship songs of the sandfly Lutzomyia longipalpis. The striking differences in the songs from 3 Brazilian populations of this sandfly with 3 distinct male pheromones support the 3 sibling species previously proposed based on this characteristic.