RESUMO
INTRODUCTION: Mitochondrial DNA has proven its utility for the study of insect evolution. Genes such as cytochrome b (Cytb) and the transfer gene for serine (SertRNA) can be used to compare closely related organisms. OBJECTIVE: The phylogenetic utility of Cytb-SertRNA-IG1-ND1 was tested for polymorphisms, and secondary structure modeling in SertRNA was done to detect possible cryptic species in Anopheles neivai. MATERIALS AND METHODS: Specimens from Colombia, Guatemala, and the type locality in Panamá were collected and sequenced for specimen comparison based on DNA polymorphisms, and secondary structure modeling for the SertRNA gene. RESULTS: Thirty-six sequences for A. neivai and A. pholidotus were obtained. CONCLUSIONS: Polymorphic variants were detected in A. neivai for Cytb-SertRNA-IG1- ND1. Despite this variation in A. neivai, cryptic species could not be detected.
Assuntos
Anopheles/genética , DNA Mitocondrial/genética , Animais , Anopheles/classificação , Colômbia , Citocromos b/genética , DNA/análise , DNA/genética , Genes de Insetos , Guatemala , Proteínas de Insetos/genética , Conformação de Ácido Nucleico , Panamá , Filogenia , Polimorfismo Genético , RNA de Transferência de Serina/genética , Especificidade da EspécieRESUMO
Abstract Introduction: Mitochondrial DNA has proven its utility for the study of insect evolution. Genes such as cytochrome b (Cytb) and the transfer gene for serine (SertRNA) can be used to compare closely related organisms. Objective: The phylogenetic utility of Cytb-SertRNA-IG1-ND1 was tested for polymorphisms, and secondary structure modeling in SertRNA was done to detect possible cryptic species in Anopheles neivai. Materials and methods: Specimens from Colombia, Guatemala, and the type locality in Panamá were collected and sequenced for specimen comparison based on DNA polymorphisms, and secondary structure modeling for the SertRNA gene. Results: Thirty-six sequences for A. neivai and A. pholidotus were obtained. Conclusions: Polymorphic variants were detected in A. neivai for Cytb-SertRNA-IG1- ND1. Despite this variation in A. neivai, cryptic species could not be detected.
Resumen Introducción. El ADN mitocondrial ha demostrado su utilidad para el estudio de la evolución en los insectos. Existen algunos genes mitocondriales como el citocromo b (Cytb) y el gen de transferencia para el aminoácido serina (SertRNA) que pueden usarse en el diagnóstico de especies estrechamente relacionadas. Objetivo. Explorar la utilidad filogenética de la región Cytb-SertRNA-IG1-ND1 para detectar posibles especies crípticas en Anopheles neivai. Materiales y métodos. Se recolectaron especímenes en Colombia, Guatemala y en la localidad tipo en Panamá, los cuales se secuenciaron y se compararon mediante el polimorfismo de ADN en toda la región y mediante la simulación de estructuras secundarias del gen SertRNA. Resultados. Se obtuvieron las secuencias de especímenes de A. neivai (34) y A. pholidotus (2). Conclusiones. Se detectaron algunos polimorfismos para la regiónCytb-SertRNA-IG1-ND1 en A. neivai, pero no así especies crípticas.
Assuntos
Animais , DNA Mitocondrial/genética , Anopheles/genética , Panamá , Filogenia , Polimorfismo Genético , Especificidade da Espécie , DNA/análise , DNA/genética , RNA de Transferência de Serina/genética , Genes de Insetos , Colômbia , Proteínas de Insetos/genética , Citocromos b/genética , Guatemala , Anopheles/classificação , Conformação de Ácido NucleicoRESUMO
The nucleotide variation and structural patterns of mitochondrial RNA molecule have been proposed as useful tools in molecular systematics; however, their usefulness is always subject to a proper assessment of homology in the sequence alignment. The present study describes the secondary structure of mitochondrial tRNA for the amino acid serine (UCN) on 13 Euptychiina species and the evaluation of its potential use for evolutionary studies in this group of butterflies. The secondary structure of tRNAs showed variation among the included species except between Hermeuptychia sp1 and sp2. Variation was concentrated in the ribotimidina-pseudouridine-cystosine (TψC), dihydrouridine (DHU) and variable loops and in the DHU and TψC arms. These results suggest this region as a potential marker useful for taxonomic differentiation of species in this group and also confirm the importance of including information from the secondary structure of tRNA to optimize the alignments.
Assuntos
Borboletas/genética , Variação Genética , Mitocôndrias/genética , Conformação de Ácido Nucleico , RNA de Transferência de Serina/genética , Alinhamento de Sequência , Animais , Sequência de Bases , Borboletas/classificação , Dados de Sequência Molecular , Filogenia , RNA de Transferência de Serina/química , Homologia de Sequência do Ácido Nucleico , Especificidade da EspécieRESUMO
UNLABELLED: Streptomycin and aminoglycoside derivatives are commonly used to treat tuberculosis and other stubborn infections; these drugs may alter auditory and/or vestibular function. Mutations in mitochondrial DNA have been associated with hypersensitivity to aminoglycosides; no studies have been conducted in Mexicans, which are very prone to such alterations because aminoglycosides have been prescribed carelessly for many years, irrespective of the ailment to be treated. AIM: We investigated "hot spot" mutations described previously as causing inner ear alterations. METHODS: Hot spot mutations at the 12S rRNA gene and the tRNA Serine (UCN) gene were screened by PCR-RFLP and sequencing in 65 subjects undergoing audiological and vestibular testing. STUDY DESIGN: Experimental. RESULTS: 32 individuals had healthy auditory and vestibular function, whereas 33 subjects had auditory affections. We found none of the previously reported mutations related to aminoglycoside hypersensitivity, or non-syndromic hearing loss. Two hearing-impaired patients that had been treated with streptomycin had the T1189C variant of the mitochondrial 12S rRNA region. CONCLUSION: Mutations related to hearing loss in other ethnic backgrounds were not found in Mexicans. However, the T1189C variant is possibly a putative mutation related to aminoglycoside hypersensitivity and was present in 2 patients.
Assuntos
Aminoglicosídeos/efeitos adversos , DNA Mitocondrial/efeitos dos fármacos , Perda Auditiva/induzido quimicamente , Mutação Puntual/efeitos dos fármacos , RNA Ribossômico/efeitos dos fármacos , RNA de Transferência de Serina/efeitos dos fármacos , Adolescente , Adulto , Idoso , Criança , Pré-Escolar , Análise Mutacional de DNA , DNA Mitocondrial/genética , Predisposição Genética para Doença , Perda Auditiva/genética , Humanos , México , Pessoa de Meia-Idade , Mutação Puntual/genética , Reação em Cadeia da Polimerase , Polimorfismo de Fragmento de Restrição , RNA Ribossômico/genética , RNA de Transferência de Serina/genética , Estreptomicina/efeitos adversos , Adulto JovemRESUMO
Streptomycin and aminoglycoside derivatives are commonly used to treat tuberculosis and other stubborn infections; these drugs may alter auditory and/or vestibular function. Mutations in mitochondrial DNA have been associated with hypersensitivity to aminoglycosides; no studies have been conducted in Mexicans, which are very prone to such alterations because aminoglycosides have been prescribed carelessly for many years, irrespective of the ailment to be treated. AIM: We investigated "hot spot" mutations described previously as causing inner ear alterations. METHODS: Hot spot mutations at the 12S rRNA gene and the tRNA Serine (UCN) gene were screened by PCR-RFLP and sequencing in 65 subjects undergoing audiological and vestibular testing. STUDY DESIGN: Experimental. RESULTS: 32 individuals had healthy auditory and vestibular function, whereas 33 subjects had auditory affections. We found none of the previously reported mutations related to aminoglycoside hypersensitivity, or non-syndromic hearing loss. Two hearing-impaired patients that had been treated with streptomycin had the T1189C variant of the mitochondrial 12S rRNA region. CONCLUSION: Mutations related to hearing loss in other ethnic backgrounds were not found in Mexicans. However, the T1189C variant is possibly a putative mutation related to aminoglycoside hypersensitivity and was present in 2 patients.
Derivados de aminoglicosídeos e estreptomicina são comumente utilizados para tratar tuberculose e outras infecções mais resistentes; esses medicamentos podem alterar a função vestibular e/ou auditiva. Mutações no DNA mitocondrial têm sido associadas à hipersensibilidade a aminoglicosídeos; não há estudos conduzidos com mexicanos, que são muito predispostos a tais alterações, uma vez que aminoglicosídeos têm sido exageradamente prescritos há anos, sem associações à doença sendo tratada. OBJETIVO: investigamos mutações "hot spot" previamente descritas como causas de alterações no ouvido interno. MÉTODOS: Mutações hot spot no gene 12S rRNA e gene SerinatRNA (UCN) foram triados pela PCR-RFLP e sequenciados em 65 indivíduos sujeitos a exames audiométricos e vestibulares. Desenho do estudo: Experimental. RESULTADOS: 32 indivíduos com funções auditiva e vestibular normais, e 33 indivíduos com doenças auditivas. Não encontramos nenhuma das mutações previamente relatadas como associadas à hipersensibilidade aos aminoglicosídeos, ou perda auditiva não-sindrômica. Dois pacientes com hipoacusia que haviam sido tratados com estreptomicina tinham a variante T1189C na região 12S rRNA. CONCLUSÃO: Mutações associadas à hipoacusia em outras etnias não foram encontradas em mexicanos. Entretanto, a variante T1189C é possivelmente uma mutação associada à hipersensibilidade a aminoglicosídeos, e esteve presente em dois pacientes.
Assuntos
Adolescente , Adulto , Idoso , Criança , Pré-Escolar , Humanos , Pessoa de Meia-Idade , Adulto Jovem , Aminoglicosídeos/efeitos adversos , DNA Mitocondrial/efeitos dos fármacos , Perda Auditiva/induzido quimicamente , Mutação Puntual/efeitos dos fármacos , RNA Ribossômico/efeitos dos fármacos , RNA de Transferência de Serina/efeitos dos fármacos , Análise Mutacional de DNA , DNA Mitocondrial/genética , Predisposição Genética para Doença , Perda Auditiva/genética , México , Reação em Cadeia da Polimerase , Polimorfismo de Fragmento de Restrição , Mutação Puntual/genética , RNA Ribossômico/genética , RNA de Transferência de Serina/genética , Estreptomicina/efeitos adversosRESUMO
Samples from 30 deaf probands exhibiting features suggestive of syndromic mitochondrial deafness or from families with maternal transmission of deafness were selected for investigation of mutations in the mitochondrial genes MT-RNR1 and MT-TS1. Patients with mutation m.1555A>G had been previously excluded from this sample. In the MT-RNR1 gene, five probands presented the m.827A>G sequence variant, of uncertain pathogenicity. This change was also detected in 66 subjects of an unaffected control sample of 306 Brazilian individuals from various ethnic backgrounds. Given its high frequency, we consider it unlikely to have a pathogenic role on hereditary deafness. As to the MT-TS1 gene, one proband presented the previously known pathogenic m.7472insC mutation and three probands presented a novel variant, m.7462C>T, which was absent from the same control sample of 306 individuals. Because of its absence in control samples and association with a family history of hearing impairment, we suggest it might be a novel pathogenic mutation.
Assuntos
DNA Mitocondrial/genética , Surdez/genética , Perda Auditiva Neurossensorial/genética , Mutação Puntual , RNA Ribossômico/genética , RNA de Transferência de Serina/genética , Brasil/epidemiologia , Surdez/etnologia , Etnicidade/genética , Feminino , Frequência do Gene , Genes Mitocondriais , Haplótipos/genética , Perda Auditiva Neurossensorial/etnologia , Humanos , Masculino , Linhagem , Reação em Cadeia da Polimerase , Polimorfismo de Fragmento de Restrição , RNA Ribossômico/fisiologia , RNA de Transferência de Serina/fisiologiaRESUMO
INTRODUCTION: Lutzomyia sand flies are involved in the transmission of the parasite Leishmania spp. in America. The taxonomy of these vectors is traditionally based on morphological features of the adult stage, particularly the paired structures of the head and genitalia. Although these characters are useful to distinguish most species of Lutzomyia, morphological identification may be complicated by the similarities within subgenera and species group. OBJECTIVE: To evaluate the utility of mitochondrial serine transfer RNA tRNA Ser for taxonomic identification of Lutzomyia. MATERIALS AND METHODS: Seven sand fly species, each representing one of the 27 taxonomic subdivisions in genus Lutzomyia, were analyzed including L. trinidadensis (Oswaldoi group), L. (Psychodopygus) panamensis, L.(Micropygomyia) cayennensis cayennensis, L. dubitans (Migonei group), L. (Lutzomyia) gomezi, L. rangeliana (ungrouped) and L. evansi (Verrucarum group). The mitochondrial tRNA Ser gene, flanked by the cytochrome b and NAD dehydrogenase subunit one genes, was extracted, amplified and sequenced from each specimen. Secondary structure of the tRNA Ser was predicted by comparisons with previously described homologous structures from other dipteran species. RESULTS: The tRNA Ser gene ranged in size from 66 base pairs in L. gomezi to 69 base pairs in L. trinidadensis. Fourteen polymorphic sites, including four insertion-deletion events, were observed in the aligned 70 nucleotide positions. The majority of the substitutions were located in the dihydrouridine, ribothymidine-pseudouridine-cytosine and variable loops, as well as in the basal extreme of the anticodon arm. CONCLUSION: Changes of primary sequence of the tRNASer provided useful molecular characters for taxonomic identification of the sand fly species under consideration.
Assuntos
Conformação de Ácido Nucleico , Psychodidae/genética , RNA de Transferência de Serina/química , RNA/química , Animais , Sequência de Bases , Insetos Vetores/genética , Dados de Sequência Molecular , Polimorfismo Genético , Psychodidae/classificação , RNA/genética , RNA Mitocondrial , RNA de Transferência de Serina/genética , Alinhamento de SequênciaRESUMO
Mitochondrial mutations are responsible for at least 1% of the cases of hereditary deafness, but the contribution of each mutation has not yet been defined in African-derived or native American genetic backgrounds. A total of 203 unselected hearing-impaired patients were screened for the presence of the mitochondrial mutation A1555G in the 12S rRNA gene and mutations in the tRNASer(UCN) gene in order to assess their frequency in the ethnically admixed Brazilian population. We found four individuals with A1555G mutation (2%), which is a frequency similar to those reported for European-derived populations in unselected samples. On the other hand, complete sequencing of the tRNASer(UCN) did not reveal reported pathogenic substitutions, namely A7445G, 7472insC, T7510C, or T7511C. Instead, other rare substitutions were found such as T1291C, A7569G, and G7444A. To evaluate the significance of these findings, 110 "European-Brazilians" and 190 "African-Brazilians" unrelated hearing controls were screened. The T1291C, A7569G and G7444A substitutions were each found in about 1% (2/190) of individuals of African ancestry, suggesting that they are probably polymorphic. Our results indicate that screening for the A1555G mutation is recommended among all Brazilian deaf patients, while testing for mutations in the tRNASer(UCN) gene should be considered only when other frequent deafness-causing mutations have been excluded or in the presence of a maternal transmission pattern.
Assuntos
Perda Auditiva/genética , Mutação/genética , RNA Ribossômico/genética , RNA de Transferência de Serina/genética , População Negra/genética , Brasil , Estudos de Casos e Controles , Análise Mutacional de DNA , Feminino , Marcadores Genéticos/genética , Predisposição Genética para Doença , Humanos , Masculino , Linhagem , Reação em Cadeia da Polimerase , RNA , RNA Mitocondrial , Índice de Gravidade de Doença , População Branca/genéticaRESUMO
Mitochondrial mutations are responsible for at least 1 percent of the cases of hereditary deafness, but the contribution of each mutation has not yet been defined in African-derived or native American genetic backgrounds. A total of 203 unselected hearing-impaired patients were screened for the presence of the mitochondrial mutation A1555G in the 12S rRNA gene and mutations in the tRNA Ser(UCN) gene in order to assess their frequency in the ethnically admixed Brazilian population. We found four individuals with A1555G mutation (2 percent), which is a frequency similar to those reported for European-derived populations in unselected samples. On the other hand, complete sequencing of the tRNA Ser(UCN) did not reveal reported pathogenic substitutions, namely A7445G, 7472insC, T7510C, or T7511C. Instead, other rare substitutions were found such as T1291C, A7569G, and G7444A. To evaluate the significance of these findings, 110 "European-Brazilians" and 190 "African-Brazilians" unrelated hearing controls were screened. The T1291C, A7569G and G7444A substitutions were each found in about 1 percent (2/190) of individuals of African ancestry, suggesting that they are probably polymorphic. Our results indicate that screening for the A1555G mutation is recommended among all Brazilian deaf patients, while testing for mutations in the tRNA Ser(UCN) gene should be considered only when other frequent deafness-causing mutations have been excluded or in the presence of a maternal transmission pattern.
Assuntos
Feminino , Humanos , Masculino , Perda Auditiva/genética , Mutação/genética , RNA Ribossômico/genética , RNA de Transferência de Serina/genética , População Negra/genética , Brasil , Estudos de Casos e Controles , Análise Mutacional de DNA , População Branca/genética , Predisposição Genética para Doença , Marcadores Genéticos/genética , Linhagem , Reação em Cadeia da Polimerase , RNA , Índice de Gravidade de DoençaRESUMO
We used mitochondrial DNA sequences from three gene regions and two tRNAs (ND4, tRNA-HIS-SER, 12S, and 16S rDNA) to investigate the historical ecology of the New World pitviper clade Agkistrodon, with emphasis on the disjunct subspecies of the cantil, A. bilineatus. We found strong evidence that the copperhead (A. contortrix) is basal to its congeners, and that the cottonmouth (A. piscivorus) is basal to cantils. Phylogeography and natural history of the living terminal taxa imply that Agkistrodon primitively occupied relatively temperate habitats, with subsequent evolution of tropicality in ancestral A. bilineatus. Our best supported phylogeny rejects three gulf arc scenarios for the biogeography of A. bilineatus. We find significant statistical support for an initial divergence between populations on the east and west coasts of México and subsequent occupancy of the Yucatán Peninsula, by way of subhumid corridors in northern Central America. Based on phylogenetic relationships, morphological and molecular divergence, and allopatry we elevate A. b. taylori of northeastern México to species status. Taylor's cantil is likely threatened by habitat destruction and small geographical range, and we offer recommendations for its conservation and management.