RESUMO
OBJECTIVES: Malaria is an important selective force for human genetic adaptation due to the sustained, lethal impact it has had on populations worldwide. High frequencies of both hemoglobin S and the null allele FYBES of the Duffy blood group have been found in areas where this disease is endemic, attributed to the protective action of the carriers of these variants against malaria infection. The objective of this work was to perform ancestral reconstruction and analyze the correlation of the frequencies of these alleles throughout the phylogeny of 24 human populations. METHODS: A tree topology and the allelic frequencies reported in the literature for the 24 populations were used. The ancestral frequencies for the two alleles were reconstructed using the maximum likelihood method and the Brownian model of evolution (CI = 95%), and the correlation analysis was performed using phylogenetically independent contrasts (PICs). Statistical analyses were performed with the statistical software R version 3.4.1. RESULTS: For both alleles, a correspondence was found in the reconstruction of the ancestral frequencies, and a significant statistical correlation (p = .001) was observed between the S and FYBES alleles. CONCLUSIONS: These results provide evidence of an epistatic relationship between the two alleles, which may influence the fitness of the individuals who present with them when they are subjected to a selective force such as malaria.
Assuntos
Hemoglobina Falciforme , Malária , Humanos , Hemoglobina Falciforme/genética , Genótipo , Alelos , Sistema do Grupo Sanguíneo Duffy/genética , Frequência do Gene , Malária/genéticaRESUMO
In regions with an Afro-descendant population and where malaria is endemic, high frequencies of polymorphisms have been found that confer resistance to this disease, such as the haemoglobin S (HbS) and Duffy genes, which provide resistance to P. falciparum and P. vivax infection, respectively. The objective of this study was to evaluate the individual and joint selection actions of these two genes in an Afro-descendant Colombian population. A total of 819 individuals were analysed using stratified random sampling. PCR-RFLP and Hardy-Weinberg equilibrium deviation analysis (H-W eq.), linkage disequilibrium (LD), D'IS2 and D'ST2 indexes, neutrality tests, correlations and fitness were performed using Arlequin 3.5.2.2 and R 3.4.1 software. In general, the population showed neutrality and H-W eq. for the HbS gene but not for the Duffy gene (FYA/FYB, FYA/FYBES and FYB/FYBES genotypes were responsible for this deviation). LD between the HbS locus and the promoter region of the Duffy gene, a value D'IS2 = 0.001 and D'ST2 = 0.020 was found, an increase in fitness of the AS*FYBES/FYBES genotype combination (marked in adolescents and adults), and a strong correlation between these genotypes (Rho = 90%, p = .001) were found, evidencing a possible joint selection action for these two alleles. This work presents evidence of the action of natural selection, both individually and jointly, on malaria resistance genes, HbS and Duffy, in the Buenaventura population.
Assuntos
Resistência à Doença/genética , Malária/epidemiologia , Malária/genética , Mutação , Seleção Genética , Alelos , Colômbia/epidemiologia , Estudos Transversais , Sistema do Grupo Sanguíneo Duffy/genética , Frequência do Gene , Aptidão Genética , Genótipo , Hemoglobina Falciforme/genética , Humanos , Desequilíbrio de Ligação , Malária/diagnóstico , Malária/parasitologia , Vigilância da População , Receptores de Superfície Celular/genéticaRESUMO
Malaria is an endemic disease in a large part of Colombia, and the city of Buenaventura reports one of the highest malaria infection rates. Some genetic variants confer resistance to malaria, such as the heterozygote for hemoglobin S (HbS) and the homozygous variant FYBES/FYBES of the Duffy gene. The aim of this work was the molecular characterization of these genes in an Afrodescendant population from the urban area of Buenaventura. A total of 819 individuals from a stratified random sampling in each of the 12 communities of this city were analyzed. Molecular analysis was performed using PCR-RFLP, and data analysis was performed using Arlequin 3.5, SPSS 20.0, and R 3.4.1. Frequencies of 3.1% and 72.2% were obtained for the S and FYBES alleles, respectively, with 6.1% AS heterozygous and 55% FYBES/FYBES homozygous genotypes. The highest percentages of the resistant genotype (genotypic combination AA*FYBES/FYBES) were found for the 13-27-year age group (8.2%) and communities 1 and 3 (18% and 10.3%, respectively). Therefore, it would be pertinent to consider the remaining communities and age groups when performing epidemiological studies and preventive and health care campaigns on malaria in the urban areas of the city of Buenaventura.
Assuntos
População Negra/genética , Sistema do Grupo Sanguíneo Duffy/genética , Hemoglobina Falciforme/genética , Malária/sangue , Polimorfismo de Fragmento de Restrição , Adolescente , Adulto , Colômbia , Feminino , Genótipo , Heterozigoto , Homozigoto , Humanos , Malária/etnologia , Malária/genética , Masculino , Reação em Cadeia da Polimerase , População Urbana , Adulto JovemRESUMO
The 5S rDNA gene is a non-coding RNA that can be found in 2 copies (type I and type II) in bony and cartilaginous fish. Previous studies have pointed out that type II gene is a paralog derived from type I. We analyzed the molecular organization of 5S rDNA type II in elasmobranchs. Although the structure of the 5S rDNA is supposed to be highly conserved, our results show that the secondary structure in this group possesses some variability and is different than the consensus secondary structure. One of these differences in Selachii is an internal loop at nucleotides 7 and 112. These mutations observed in the transcribed region suggest an independent origin of the gene among Batoids and Selachii. All promoters were highly conserved with the exception of BoxA, possibly due to its affinity to polymerase III. This latter enzyme recognizes a dT4 sequence as stop signal, however in Rajiformes this signal was doubled in length to dT8. This could be an adaptation toward a higher efficiency in the termination process. Our results suggest that there is no TATA box in elasmobranchs in the NTS region. We also provide some evidence suggesting that the complexity of the microsatellites present in the NTS region play an important role in the 5S rRNA gene since it is significantly correlated with the length of the NTS.
Assuntos
Elasmobrânquios/genética , RNA Ribossômico 5S/genética , Animais , Mutação , Conformação de Ácido Nucleico , RNA Ribossômico 5S/química , Especificidade da Espécie , Regiões Terminadoras Genéticas , Transcrição GênicaRESUMO
The Andes of South America hosts perhaps the highest amphibian species diversity in the world, and a sizable component of that diversity is comprised of direct-developing frogs of the genus Pristimantis (Anura: Craugastoridae). In order to better understand the initial stages of species formation in these frogs, this study quantified local-scale spatial genetic structuring in three species of Pristimantis. DNA sequences of two mitochondrial gene fragments (16S and COI) were obtained from P. brevifrons, P. palmeri and P. jubatus at different locations in the Cordillera Occidental. We found high levels of genetic diversity in the three species, with highly structured populations (as measured by F(ST)) in P. brevifrons and P. palmeri while P. jubatus showed panmixia. Large effective population sizes, inferred from the high levels of genetic diversity, were found in the three species and two highly divergent lineages were detected within P. jubatus and P. palmeri. Estimated divergence times among populations within P. brevifrons and P. palmeri coincide with the Pleistocene, perhaps due to similar responses to climatic cycling or recent geological history. Such insights have important implications for linking alpha and beta diversity, suggesting regional scale patterns may be associated with local scale processes in promoting differentiation among populations in the Andes.
Assuntos
Anuros/classificação , Anuros/genética , Filogeografia/métodos , Animais , Colômbia , DNA Mitocondrial/genética , Variação Genética/genética , Geografia , Haplótipos/genéticaRESUMO
The Hartón del Valle(HV)cattleisa Criollo breed of Spanish descent that has adapted to the conditionsof the Cauca valley (Colombia). This breed is currently listed as “vulnerable” because its population has dramatically declined in the last two years. Prompted by the uncertain future of this breed and its importance as a potential resource of valuable genes. Objective: this study addressed the diversity, genetic structure and ancestry of HV cattle using mitochondrial DNA (mtDNA). Methods: a 350-bp fragment was amplified and sequenced from 72 HV animals in 9 separate farms and from animals of Brahman and Holstein breeds. To analyze the breed's ancestry, the sequences were compared with 560 sequences available in the GenBank, representing 50 Bos taurus and Bos indicus breeds. Results: in accordance with the Spanish origin of the HV breed, there was a high representation of European mtDNA (91.7%) and a low representation of African (5.5%) and Middle Eastern mtDNA (2.7%). The average haplotype diversity was 0.65 ± 0.05. The farm with the oldest ancestry was the only population in which three mitochondrial lineages were observed; unfortunately, it was recently depopulated. Proximity was observed between HV and two Columbian breeds, the Romosinuano and Costeño con Cuernos. A comparative analysis with the sequences deposited in the GenBank from numerous breeds revealed the presence of 37 haplotypes, seven of which were unique to HV. Conclusions: the following Iberian breeds were found to be most closely related to HV: Tudanca, Rubia Gallega, Negra Serrana, Murciana, Pajuna, Avileña, Garvonesa and Mertolenga. Phylogenetic analysis confirmed the Iberian ancestry and some African influence on this Latin American Criollo breed.
El Hartón del Valle (HV),es una raza adaptada a las condiciones del Valle del Cauca(Colombia) que está catalogada como “vulnerable” y cuya población ha descendido drásticamente en los últimos dos años. Objetivo: debido al futuro incierto y a la importancia como recurso potencial en la seguridad alimentaria regional se abordó el estudio de la diversidad, la estructura genética y la ancestría del HV, mediante ADN mitocondrial (ADNmt). Métodos: se amplificó y secuenció un fragmento de 350 pb en 72 animales HV, provenientes de nueve poblaciones y de controles de las razas Brahman y Holstein. Para analizar la ancestría las secuencias fueron comparadas con 560 secuencias de 50 razas Bos taurus y Bos indicus, depositadas en el GenBank. Resultados: de acuerdo con su origen español, se encontró una marcada influencia del ADNmt europeo (91.7%) y baja participación de taurinos de origen africano (5.5%) y del cercano Oriente (2.7%). La diversidad haplotípica promedio fue 0.65 ± 0.05. El hato más antiguo fue el único que mostró los tres linajes mitocondriales, sin embargo, este ha sido liquidado recientemente. Se observó proximidad entre el HV con las razas colombianas Romosinuano y Costeño con Cuernos. La comparación con las secuencias depositadas en el GenBank con diferentes razas reveló la presencia de 37 haplotipos, de los cuales siete fueron únicos en el HV. Conclusiones: las razas ibéricas más cercanas al HV fueron: Tudanca, Rubia Gallega, Negra Serrana, Murciana, Pajuna, Avileña, Garvonesa y Mertolenga. El árbol filogenético confirmó la ancestralidad ibérica y la influencia africana en las razas criollas de América Latina.
O Hartón del Valle (HV) é uma raça adaptada às condições da região pertencente ao departamento do Valle del Cauca (Colombia). A raça está catalogada como vulnerável já que sua população tem sido reduzida drasticamente nos últimos dois anos. Objetivo: devido a incerteza no futuro da raça e a sua importancia como recurso potencial na segurança alimentaria regional, abordou-se o estudo da diversidade, a estrutura genética e a ancestralidade do gado HV, utilizando DNA mitocondrial (mtDNA). Métodos: para isto, se amplificou e sequenciou um fragmento de 350 pares de bases em 72 animais provenientes de nove populações e também de controles das raças Brahman e Holandesa. Para analizar a ancestralidade das sequências, estas foram comparadas com outras 560 de 50 raças Bos taurus y Bos indicus depositadas no genebank. Resultados: de acordo com sua origem espanhola, foi encontrada uma marcada influência do DNA mitocondrial europeu (91.7%), e baixa participação de taurinos de origem africana (5.5%) e do Oriente Próximo (2.7%). A média da diversidade haplotípica foi de 0.65 ± 0.05. A população de gado HV mais antiga foi a única que apresentou as três linhagens mitocondriais encontradas; embora, esta população foi terminada recentemente. Observou-se também proximidade do gado HV com as raças colombianas da região Caribe, Romosinuano e Costeño con Cuernos. A comparação com as sequências depositadas no genebank com diferentes raças revelou a presença de 37 haplotipos, dos quais sete foram únicos no HV. Conclusões: as raças ibéricas mais aproximadas do HV foram: Tudanca, Rubia Gallega, Negra Serrana, Murciana, Pajuna, Avileña Garvonesa e Mertolenga. A árvore filogenética confirmou sua ancestralidade ibérica e a influência africana nas raças crioulas da América Latina.
RESUMO
Para estimar el efecto de la densidad poblacional de huevos sobre la viabilidad huevoadulto de Drosophila melanogaster se realizaron tres tratamientos en frascos con medio de cultivo agar-banano: a densidad de 10, 50 y 90 huevos. La variable de respuesta fue la proporción de individuos adultos emergidos desde la aparición del primer imago hasta 15 días después de la siembra. Las viabilidades huevo-adulto promedio fueron 0,320, 0,338 y 0,328 para las densidades de 10, 50 y 90 huevos respectivamente. No se evidenciaron diferencias significativas entre los tres tratamientos (p>0.05). Por lo tanto, no se detectó en este estudio influencia de la densidad poblacional de huevos sobre la viabilidad huevo-adulto. Probablemente debido a que la proporción entre el número de huevos y la cantidad de medio fue suficientemente alta para no generar competencia en otros estadios del desarrollo huevo/adulto.
For estimating the effect from population density of eggs over viability egg-adult in Drosophila melanogaster, it was made three treatments in flasks with agar-banana culture media: densities of 10, 50 and 90 eggs. The effect evaluated was the adults proportion that emerged after 15 days of planting. The mean proportions of viability egg-adult were 0.32, 0.338 and 0.328 for the density of 10, 50 and 90 eggs respectively. Significant differences in viability were not evident (p>0.05). Consequently, it was not found effects from the eggs densities in the present study over egg-adult viability. These results probably were due to that the relation among number of eggs and quantity of culture media was not enough of a high for generate competition at another stadiums through the egg-adult development.
RESUMO
The genetic variation and population structure of three populations of Anopheles darlingi from Colombia were studied using random amplified polymorphic markers (RAPDs) and amplified fragment length polymorphism markers (AFLPs). Six RAPD primers produced 46 polymorphic fragments, while two AFLP primer combinations produced 197 polymorphic fragments from 71 DNA samples. Both of the evaluated genetic markers showed the presence of gene flow, suggesting that Colombian An. darlingi populations are in panmixia. Average genetic diversity, estimated from observed heterozygosity, was 0.374 (RAPD) and 0.309 (AFLP). RAPD and AFLP markers showed little evidence of geographic separation between eastern and western populations; however, the F ST values showed high gene flow between the two western populations (RAPD: F ST = 0.029; Nm: 8.5; AFLP: F ST = 0.051; Nm: 4.7). According to molecular variance analysis (AMOVA), the genetic distance between populations was significant (RAPD:phiST = 0.084; AFLP:phiST = 0.229, P < 0.001). The F ST distances and AMOVAs using AFLP loci support the differentiation of the Guyana biogeographic province population from those of the Chocó-Magdalena. In this last region, Chocó and Córdoba populations showed the highest genetic flow.
Assuntos
Anopheles/genética , Genes de Insetos/genética , Variação Genética/genética , Genética Populacional , Animais , Anopheles/classificação , Sequência de Bases , Colômbia , Marcadores Genéticos/genética , Geografia , Dados de Sequência Molecular , Análise Multivariada , Filogenia , Reação em Cadeia da Polimerase , Polimorfismo de Fragmento de Restrição , Técnica de Amplificação ao Acaso de DNA PolimórficoRESUMO
The genetic variation and population structure of three populations of Anopheles darlingi from Colombia were studied using random amplified polymorphic markers (RAPDs) and amplified fragment length polymorphism markers (AFLPs). Six RAPD primers produced 46 polymorphic fragments, while two AFLP primer combinations produced 197 polymorphic fragments from 71 DNA samples. Both of the evaluated genetic markers showed the presence of gene flow, suggesting that Colombian An. darlingi populations are in panmixia. Average genetic diversity, estimated from observed heterozygosity, was 0.374 (RAPD) and 0.309 (AFLP). RAPD and AFLP markers showed little evidence of geographic separation between eastern and western populations; however, the F ST values showed high gene flow between the two western populations (RAPD: F ST = 0.029; Nm: 8.5; AFLP: F ST = 0.051; Nm: 4.7). According to molecular variance analysis (AMOVA), the genetic distance between populations was significant (RAPD:phiST = 0.084; AFLP:phiST = 0.229, P < 0.001). The F ST distances and AMOVAs using AFLP loci support the differentiation of the Guyana biogeographic province population from those of the Chocó-Magdalena. In this last region, Chocó and Córdoba populations showed the highest genetic flow.
Assuntos
Animais , Anopheles/genética , Variação Genética , Genética Populacional , Genes de Insetos/genética , Anopheles/classificação , Sequência de Bases , Colômbia , Geografia , Marcadores Genéticos/genética , Dados de Sequência Molecular , Análise Multivariada , Filogenia , Reação em Cadeia da Polimerase , Polimorfismo de Fragmento de Restrição , Técnica de Amplificação ao Acaso de DNA PolimórficoRESUMO
Random amplified polymorphic DNA (RAPD) markers were used to analyze 119 DNA samples of three Colombian Anopheles nuneztovari populations to study genetic variation and structure. Genetic diversity, estimated from heterozygosity, averaged 0.34. Genetic flow was greater between the two populations located in Western Colombia (F ST: 0.035; Nm: 6.8) but lower between these two and the northeastern population (F ST: 0.08; Nm: 2.8). According to molecular variance analysis, the genetic distance between populations was significant (phi ST 0.1131, P < 0.001). The variation among individuals within populations (phi ST 0.8869, P < 0.001)was also significant, suggesting a greater degree of population subdivision, not considered in this study. Both the parameters evaluated and the genetic flow suggest that Colombian An. nuneztovari populations are co-specific.
Assuntos
Anopheles/genética , Genes de Insetos/genética , Heterozigoto , Animais , Sequência de Bases , Colômbia , Marcadores Genéticos , Variação Genética/genética , Dados de Sequência Molecular , Análise Multivariada , Filogenia , Técnica de Amplificação ao Acaso de DNA PolimórficoRESUMO
Random amplified polymorphic DNA (RAPD) markers were used to analyze 119 DNA samples of three Colombian Anopheles nuneztovari populations to study genetic variation and structure. Genetic diversity, estimated from heterozygosity, averaged 0.34. Genetic flow was greater between the two populations located in Western Colombia (F ST: 0.035; Nm: 6.8) but lower between these two and the northeastern population (F ST: 0.08; Nm: 2.8). According to molecular variance analysis, the genetic distance between populations was significant (phiST 0.1131, P < 0.001). The variation among individuals within populations (phiST 0.8869, P < 0.001)was also significant, suggesting a greater degree of population subdivision, not considered in this study. Both the parameters evaluated and the genetic flow suggest that Colombian An. nuneztovari populations are co-specific
