Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 8 de 8
Filtrar
Más filtros










Base de datos
Intervalo de año de publicación
1.
Nat Commun ; 15(1): 172, 2024 Jan 03.
Artículo en Inglés | MEDLINE | ID: mdl-38172616

RESUMEN

Several African mammals exhibit a phylogeographic pattern where closely related taxa are split between West/Central and East/Southern Africa, but their evolutionary relationships and histories remain controversial. Bushpigs (Potamochoerus larvatus) and red river hogs (P. porcus) are recognised as separate species due to morphological distinctions, a perceived lack of interbreeding at contact, and putatively old divergence times, but historically, they were considered conspecific. Moreover, the presence of Malagasy bushpigs as the sole large terrestrial mammal shared with the African mainland raises intriguing questions about its origin and arrival in Madagascar. Analyses of 67 whole genomes revealed a genetic continuum between the two species, with putative signatures of historical gene flow, variable FST values, and a recent divergence time (<500,000 years). Thus, our study challenges key arguments for splitting Potamochoerus into two species and suggests their speciation might be incomplete. Our findings also indicate that Malagasy bushpigs diverged from southern African populations and underwent a limited bottleneck 1000-5000 years ago, concurrent with human arrival in Madagascar. These results shed light on the evolutionary history of an iconic and widespread African mammal and provide insight into the longstanding biogeographic puzzle surrounding the bushpig's presence in Madagascar.


Asunto(s)
Mamíferos , Humanos , Animales , Porcinos , Madagascar , Filogenia , Porosidad , Filogeografía , Mamíferos/genética
2.
Sci Rep ; 10(1): 20629, 2020 11 26.
Artículo en Inglés | MEDLINE | ID: mdl-33244111

RESUMEN

The island of Madagascar, situated off the southeast coast of Africa, shows the first evidence of human presence ~ 10,000 years ago; however, other archaeological data indicates a settlement of the modern peoples of the island distinctly more recent, perhaps > 1500 years ago. Bushpigs of the genus Potamochoerus (family Suidae), are today widely distributed in Madagascar and presumed to have been introduced from Africa at some stage by human immigrants to the island. However, disparities about their origins in Madagascar have been presented in the literature, including the possibility of endemic subspecies, and few empirical data are available. Furthermore, the separation of bushpigs in Madagascar from their mainland relatives may have favoured the evolution of a different repertoire of immune genes first due to a founder effect and then as a response to distinct pathogens compared to their ancestors. Molecular analysis confirmed the species status of the bushpig in Madagascar as P. larvatus, likely introduced from the central region of southern Africa, with no genetic evidence for the recognition of eastern and western subspecies as suggested from previous cranial morphology examination. Investigation of the immunologically important SLA-DQB1 peptide-binding region showed a different immune repertoire of bushpigs in Madagascar compared to those on the African mainland, with seventeen exon-2 haplotypes unique to bushpigs in Madagascar (2/28 haplotypes shared). This suggests that the MHC diversity of the Madagascar populations may have enabled Malagasy bushpigs to adapt to new environments.


Asunto(s)
Porcinos/genética , África Austral , Animales , Variación Genética/genética , Haplotipos , Humanos , Madagascar , Filogenia
4.
Artículo en Inglés | MEDLINE | ID: mdl-32197367

RESUMEN

The geographical distribution and impact on animal and human health of both West Nile and Usutu viruses, two flaviviruses of the Japanese encephalitis complex, have been increasing during the past two decades. Both viruses circulate in Europe and Africa within a natural cycle between wild birds and mosquitoes, mainly from the Culex genus. We retrospectively analyzed sera from domestic and wild birds sampled in 2008 in two wetlands, namely the Inner Niger Delta, Mali, and the Lake Alaotra area, Madagascar. Sera were first tested using a commercial ID Screen West Nile Competition Multi-species ELISA kit. Then, positive sera and sera with insufficient volume for testing with ELISA were tested with a Microneutralization Test. In Mali, the observed seroprevalence in domestic birds was 28.5% [24.5; 32.8] 95%CI, 3.1 % [1.8; 5.2] 95%CI, 6.2% [3.4; 10.2] 95%CI and 9.8 % [7.3; 12.8] 95%CI, for West Nile virus (WNV), Usutu virus (USUV), undetermined flavivirus, and WNV/USUV respectively. Regarding domestic birds of Madagascar, the observed seroprevalence was 4.4 % [2.1; 7.9]95%CI for WNV, 0.9% [0.1; 3.1] 95%CI for USUV, 1.3% [0.5; 2.8] 95%CI for undetermined flavivirus, and null for WNV/USUV. Among the 150 wild birds sampled in Madagascar, two fulvous whistling-ducks (Dendrocygna bicolor) were positive for WNV and two for an undetermined flavivirus. One white-faced whistling-duck (Dendrocygna viduata) and one Hottentot teal (Spatula hottentota) were tested positive for USUV. African and European wetlands are linked by wild bird migrations. This first detection of USUV-as well as the confirmed circulation of WNV in domestic birds of two wetlands of Mali and Madagascar-emphasizes the need to improve the surveillance, knowledge of epidemiological patterns, and phylogenetic characteristics of flavivirus in Africa, particularly in areas prone to sustained, intense flavivirus transmission such as wetlands.


Asunto(s)
Aves , Infecciones por Flavivirus , Flavivirus , Fiebre del Nilo Occidental , Virus del Nilo Occidental , Adulto , Animales , Aves/virología , Femenino , Flavivirus/aislamiento & purificación , Humanos , Madagascar , Masculino , Malí , Filogenia , Estudios Retrospectivos , Estudios Seroepidemiológicos , Humedales
5.
Mitochondrial DNA A DNA Mapp Seq Anal ; 27(6): 4543-4544, 2016 11.
Artículo en Inglés | MEDLINE | ID: mdl-27159683

RESUMEN

The complete mitochondrial genome of the Aldabra giant tortoise [Aldabrachelys gigantea (Schweigger, 1812): Reptilia, Testudines, Testudinidae] was sequenced using a shotgun approach on an Illumina HiSeq 2500 platform (Illumina Inc., San Diego, CA). This genome was 16 467 bp long and presents the typical organization found in vertebrates. The mean coverage of sequencing was 116×. A phylogenetic analysis of the Testudinidae confirms the placement of Aldabrachelys in an Indian Ocean group (including Madagascar). This mitogenome constitutes a reference for ancient DNA analyses of the extinct Madagascan lineages of Aldabrachelys.


Asunto(s)
Genoma Mitocondrial , Tortugas/genética , Animales , ADN/química , ADN/aislamiento & purificación , ADN/metabolismo , ADN Mitocondrial/química , ADN Mitocondrial/clasificación , ADN Mitocondrial/genética , Secuenciación de Nucleótidos de Alto Rendimiento , Filogenia , Análisis de Secuencia de ADN , Tortugas/clasificación
7.
Eur J Wildl Res ; 61(4): 635-639, 2015.
Artículo en Inglés | MEDLINE | ID: mdl-32214942

RESUMEN

To date, infectious bronchitis virus (IBV) is potentially found in wild birds of different species. This work reports the survey of coronaviruses in wild birds from Madagascar based on the targeting of a conserved genome sequence among different groups of CoVs. Phylogenetic analyses revealed the presence of gammacoronaviruses in different species of Gruiformes, Passeriformes, Ciconiiformes, Anseriformes, and Charadriiformes. Furthermore, some sequences were related to various IBV strains. Aquatic and migratory birds may play an important role in the maintenance and spread of coronaviruses in nature, highlighting their possible contribution in the emergence of new coronavirus diseases in wild and domestic birds.

8.
PLoS One ; 7(6): e39859, 2012.
Artículo en Inglés | MEDLINE | ID: mdl-22768146

RESUMEN

Recent growth in industrialization and the modernization of agricultural activities, combined with human population growth, has greatly modified China's natural environment, particularly in the vicinity of large cities. We compared avifauna checklists made between 1877 and 1938 with current checklists to determine the extent of local bird extinctions during the last century in the greater Beijing area. Our study shows that of the 411 bird species recorded from 1877-1938, 45 (10.9%) were no longer recorded from 2004-2006. Birds recorded as 'rare' in 1938 were more likely to have disappeared in subsequent years. Migrant status also influenced the probability of local bird extinction with winter migrants being the most affected class. Moreover, larger birds were more likely to have disappeared than smaller ones, potentially explained by differential ecological requirements and anthropogenic exploitation. Although our habitat descriptions and diet classification were not predictors of local bird extinction, the ecological processes driving local bird extinction are discussed in the light of historical changes that have impacted this region since the end of the 1930 s. Our results are of importance to the broader conservation of bird wildlife.


Asunto(s)
Aves/fisiología , Ecosistema , Extinción Biológica , Migración Animal/fisiología , Animales , Aves/anatomía & histología , Tamaño Corporal , China , Geografía , Historia del Siglo XIX , Historia del Siglo XX , Historia del Siglo XXI , Humanos , Modelos Biológicos
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA
...