Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 6 de 6
Filtrar
1.
J Econ Entomol ; 116(3): 1033-1037, 2023 06 13.
Artículo en Inglés | MEDLINE | ID: mdl-37156231

RESUMEN

Reticulitermes flavipes is the most invasive species in its genus and is responsible for causing significant damage to human structures in areas where it has been introduced. Although it has already become established in Chile and Uruguay, it had not previously been reported in Argentina. In this study, we report the first detection of this species in Buenos Aires, the capital of Argentina. The colony was already producing alates, and species identification was confirmed through both morphology and mitochondrial gene 16S rRNA analysis. Our results, while not conclusive, suggest that this introduction was independent from the one that occurred in Chile and Uruguay, and potentially originated from the United States. The detection of R. flavipes in Argentina is significant because it highlights the potential for this species to establish itself in new regions and underscores the need for future research on and control of R. flavipes in this country.


Asunto(s)
Isópteros , Humanos , Animales , Argentina , ARN Ribosómico 16S/genética , Uruguay
2.
Science ; 370(6522): 1343-1348, 2020 12 11.
Artículo en Inglés | MEDLINE | ID: mdl-33303617

RESUMEN

The tropics are the source of most biodiversity yet inadequate sampling obscures answers to fundamental questions about how this diversity evolves. We leveraged samples assembled over decades of fieldwork to study diversification of the largest tropical bird radiation, the suboscine passerines. Our phylogeny, estimated using data from 2389 genomic regions in 1940 individuals of 1283 species, reveals that peak suboscine species diversity in the Neotropics is not associated with high recent speciation rates but rather with the gradual accumulation of species over time. Paradoxically, the highest speciation rates are in lineages from regions with low species diversity, which are generally cold, dry, unstable environments. Our results reveal a model in which species are forming faster in environmental extremes but have accumulated in moderate environments to form tropical biodiversity hotspots.


Asunto(s)
Biodiversidad , Aves/clasificación , Aves/genética , Animales , Especiación Genética , Filogenia
3.
J Clin Microbiol ; 46(11): 3822-5, 2008 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-18768653

RESUMEN

This study evaluated the biodiversity of 28 clinical and 24 environmental Mycobacterium isolates from Rio de Janeiro, Brazil, by using hsp65 sequences, with the aim of contributing to a better understanding of the genetic diversity and usefulness of this marker. An extensive phylogenetic analysis was performed. The nucleotide diversity was similar between clinical (0.06508) and environmental (0.06221) isolates.


Asunto(s)
Proteínas Bacterianas/genética , Biodiversidad , Chaperoninas/genética , Microbiología Ambiental , Mycobacterium/clasificación , Mycobacterium/aislamiento & purificación , Tuberculosis/microbiología , Animales , Brasil/epidemiología , Bovinos , Chaperonina 60 , ADN Bacteriano/química , ADN Bacteriano/genética , Humanos , Datos de Secuencia Molecular , Mycobacterium/genética , Filogenia , Análisis de Secuencia de ADN , Porcinos , Tuberculosis/epidemiología
4.
Ciênc. rural ; Ciênc. rural (Online);45(5): 877-883, 05/2015. tab
Artículo en Inglés | LILACS | ID: lil-745832

RESUMEN

This study aimed to investigate the genetic variability of two Brazilian free range (Caipira) chickens lines using microsatellites analysis of ten loci. It was collected a total of 99 blood samples, which 49 were from Paraíso Pedrês (PP) and 50 were from Rubro Negra (RN) lines. The amplification of the DNA fragments was performed by polymerase chain reaction (PCR) and the genotyping was conduct using ABI 3130 sequencer. The allele number variation was among 3 (LEI0254) to 32 (LEI0212) in the PP line, and 4 (LEI0254) to 31 (LEI0212) in the RN line. The allelic average per locus was 13.3 and 13.1 in the PP and RN lines, respectively. The average observed and the expected heterozygosity were 0.650 and 0.820 in the PP line, and 0.671 and 0.804 in the RN line. All of the analyzed loci were informative (PIC>0.5). These results indicate that these free-range animals have a high genetic variability, at least for the majority of the analyzed loci, and this genetic variation is higher than the commercial chickens and similar for the no-commercial birds.


Este trabalho teve como objetivo investigar a variabilidade genética de duas linhagens de galinhas caipiras brasileiras usando 10 locos de microssatélites. Noventa e nove amostras de sangue total foram coletadas, sendo 49 da linhagem Paraíso Pedrês (PP) e 50 da linhagem Rubro Negra (RN). As amplificações dos fragmentos do DNA foram realizadas pela técnica da reação em cadeia pela polimerase (PCR), e a genotipagem ocorreu em um sequenciador ABI 3130. O número de alelos variou de 3 (LEI0254) a 32 (LEI0212), na linhagem PP, e de 4 (LEI0254) a 31 (LEI0212), na linhagem RN. O número médio de alelos por loco foi de 13,3 e de 13,1 nas linhagens PP e RN, respectivamente. A heterozigosidade observada média e a heterozigosidade esperada média foram 0,650 e 0,820, na linhagem PP, e 0,671 e 0,804, na linhagem RN. Todos os locos analisados foram informativos (PIC>0,5). Estes resultados indicam que estes animais caipiras têm uma grande variabilidade genética, pelo menos para a maioria dos locos analisados, e que esta variação genética é maior do que a das galinhas comerciais e semelhante à de aves não comerciais.

5.
Pesqui. vet. bras ; Pesqui. vet. bras;34(1): 98-102, jan. 2014. tab
Artículo en Inglés | LILACS | ID: lil-707119

RESUMEN

The purpose of this study was to investigate the genetic polymorphism of fifteen microsatellites loci in Brazilian (blue-egg Caipira) chickens. Samples were collected from 100 blue eggs of Caipira chickens from rural properties in the city of Dois Lajeados, RS. After DNA extraction, the fragments related to molecular markers LEI0248, LEI0221, LEI0214, LEI0192, LEI0217, LEI0254, LEI0194, LEI0212, MCW0371, ADL0278, LEI0234, MCW0183, MCW0216, MCW0330 and MCW0081 were obtained by polymerase chain reaction (PCR). The statistical analysis were carried out with the softwares ARLEQUIN 3.5 version and CERVUS 3.0.3 version. The allelic and genotypic frequencies, deviations from Hardy-Weinberg equilibrium, estimates of observed (HO) and expected (HE) heterozygosity and polymorphic information content (PIC) were obtained for each marker locus. A total of 186 alleles from 15 loci were obtained, with sizes ranging of 83 to 490 base pairs. The medium number of alleles was 12.4, the HE was 0.76±0.14 and HO was 0.49±0.21 and PIC was 0.706. The first conclusion is that the microsatellites used are polymorphic and can be used to genetic studies in chickens. The second is that the "Caipira" chicken (blue eggs) population investigated has a great genic variability, which makes than an important source of genetic resources for future animal breeding programs.


O objetivo deste trabalho foi investigar a variabilidade genética de quinze loci de microssatélites em galinhas caipiras brasileiras de ovos azuis. Foram coletadas amostras de sangue de 100 galinhas caipiras brasileiras de ovos azuis provenientes de propriedades da região rural do município de Dois Lajeados, RS. Após extração do DNA foram utilizados marcadores para quinze loci de microssatélites: LEI0248, LEI0221, LEI0214, LEI0192, LEI0217, LEI0254, LEI0194, LEI0212, MCW0371, ADL0278, LEI0234, MCW0183, MCW0216, MCW0330 e MCW0081 que foram amplificados por meio da técnica de reação em cadeia da polimerase (PCR). A análise estatística foi conduzida utilizando o programa ARLEQUIN ver 3.5 e CERVUS ver 3.0.3. Foram determinadas às frequências alélicas, genotípicas e estimativas de heterozigosidade esperada (HE) e observada (HO), desvios do Equilíbrio de Hardy-Weinberg e conteúdo de informação polimórfica (PIC) para cada locus de microssatélite. Os resultados demonstraram um total de 186 alelos (somando os alelos dos 15 loci), com os fragmentos variando entre 83 e 490 pares de base, com número médio de alelos de 12,4, HE de 0,76±0,14 e HO de 0,49±0,21 e PIC de 0,706. Conclui-se que os microssatélites utilizados são polimórficos e que podem, portanto, serem utilizados para investigações genéticas em galinhas. A população de galinhas caipiras de ovos azuis analisada apresenta grande variabilidade gênica, o que as torna uma importante fonte de recursos genéticos, e que poderão, assim, serem utilizadas em futuros programas de melhoramento genético animal.


Asunto(s)
Animales , Femenino , Pollos/genética , Polimorfismo Genético , Variación Genética/genética , Sitios Genéticos , Reacción en Cadena de la Polimerasa
6.
Ann Hum Biol ; 33(2): 142-60, 2006.
Artículo en Inglés | MEDLINE | ID: mdl-16684689

RESUMEN

BACKGROUND: Alu insertions provide useful markers for the study of inter-population affinities and historical processes, but data on these systems are not numerous in Native Americans and related populations. AIM: The study aimed to answer the following questions: (a) do the population relationships found agree with ethnic, historical and geographical data? and (b) what can heterozygote levels and associated results inform us about the events that led to the colonization of the New World? SUBJECTS AND METHODS: Twelve Alu insertion polymorphisms were studied in 330 individuals belonging to South American Native, Siberian and Mongolian populations. These data were integrated with those from 526 persons, to ascertain the relationships between Asian, Northern Arctic and Amerindian populations. RESULTS: A decreasing trend concerning heterozygosities and amount of gene flow was observed in the three sets, in the order indicated above. Most results indicated the validity of these subdivisions. However, no clear structure could be observed within South American Natives, indicating the importance of dispersive (genetic drift, founder effects) factors in their differentiation. CONCLUSIONS: The answers to the questions are: (a) yes; and (b) an initial moderate bottleneck, intensified by more recent historical events (isolation and inbreeding), can explain the current Amerindian pattern of diversity.


Asunto(s)
Elementos Alu/genética , Pueblo Asiatico/genética , Etnicidad/genética , Genética de Población , Indígenas Norteamericanos/genética , Mutagénesis Insercional , Polimorfismo Genético , Emigración e Inmigración/historia , Femenino , Frecuencia de los Genes , Marcadores Genéticos , Heterocigoto , Historia Antigua , Humanos , Indígenas Sudamericanos/genética , Masculino , Análisis de Componente Principal , Siberia/etnología
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA