RESUMO
We have sampled five different herds of caribou in Alaska to ascertain their major histocompatibility complex (MHC) class II diversity, and to assess whether the herds were significantly different in their MHC class II allele profiles. We complemented the MHC results with data from nine neutral microsatellite markers. The results indicate that while the microsatellites are diverse, there are no significant differences between the herds. However, for the MHC, we have shown that there is diversity at three of the four loci studied, the different herds have significantly different MHC class II allele profiles. It is also clear that although some of the herds have overlapping ranges, they are still different for their MHC class II alleles.
Assuntos
Variação Genética , Antígenos de Histocompatibilidade Classe II/genética , Rena/genética , Alaska , Animais , Regulação da Expressão Gênica , Frequência do Gene/genética , Loci Gênicos/genética , Geografia , Haplótipos/genética , Repetições de Microssatélites/genética , Especificidade da EspécieRESUMO
This study describes surveillance for avian influenza viruses (AIV) in the Minto Flats State Game Refuge, high-density waterfowl breeding grounds in Alaska. Five hundred paired cloacal samples from dabbling ducks (Northern Pintail, Mallard, Green Wing Teal, and Widgeon) were placed into ethanol and viral transport medium (VTM). Additional ethanol-preserved samples were taken. Of the ethanol-preserved samples, 25.6% were AIV RNA-positive by real-time RT-PCR. The hemagglutinin (HA) and neuraminidase (NA) subtypes were determined for 38 of the first-passage isolates, and four first-passage isolates could not be definitively subtyped. Five influenza A virus HA-NA combinations were identified: H3N6, H3N8, H4N6, H8N4, and H12N5. Differences in the prevalence of AIV infections by sex and by age classes of Northern Pintail and Mallard ducks were detected, but the significance of these differences is undefined. In the 500 paired samples, molecular screening detected positive birds at a higher rate than viral isolation (chi(2) = 8.35, p = 0.0035, df = 1); however, 20 AIV isolates were recovered from PCR-negative ducks. Further research is warranted to compare the two screening protocols' potential for estimating true prevalence in wild birds. Our success during 2005 indicates Minto Flats will be a valuable study site for a longitudinal research project designed to gain further insight into the natural history, evolution, and ecology of AIV in wild birds.