On the basis of studies with animal models, the gene for the low-affinity receptor for immunoglobulin E (IgE) (FCER2, CD23) has been implicated as a candidate for IgE-mediated allergic diseases and bronchial hyperreactivity, or related traits. Given evidence for genetic complexity in atopic disorders, we sought to study two European subpopulations, Finnish and Catalonian. We studied three phenotypic markers: (1) total serum IgE level; (2) asthma; and (3) specific IgE level for a mixture of the most common aeroallergens in Finland. Altogether, eight polymorphic markers spanning a region of 10 cM around the FCER2 gene on chromosome 19p13 were analyzed in 124 families. The physical order of the markers and the location of the FCER2 gene were confirmed by using radiation hybrids. The allele and haplotype association study showed a suggestive haplotype association (significance of p = 0.03 based on a permutation test) for a high serum IgE response. In a subset of chromosomes segregating with asthma in families with two or more affected members, a single haplotype was found to be highly enriched (p = 8.3 x 10(-6)). However, sequence polymorphisms, which would verify structural differences in the FCER2 gene, were not detected in the coding region of the receptor. Our results suggest that chromosome 19p13 might harbor a genetic determinant of IgE-related traits. Studies in other population samples are needed to verify this finding.
The brood size in the Finnish Northern Goshawks seems to be associated with the breeding habitat and the availability of suitable prey. In this study, we examined these relationships in three study areas of different landscape structure in southern Finland, including a recently colonized urban area. The most abundant prey categories found in the food remains of the goshawk included corvids, turdids, columbids, gallinaceous birds, and squirrels. Corvids dominated in the diet samples of all the study areas. The number of turdids and columbids in the samples was significantly higher in both the rural and the urban habitats than in the wilderness area. The number of gallinaceous birds was significantly higher in the wilderness area than in other habitats. Gallinaceous birds, particularly tetraonids, the traditional staple food of the Northern Goshawk in Finland, seemed to be largely compensated by corvids in the wilderness area and by corvids and columbids in the rural and urban areas. The amount of corvids in prey showed a positive relationship with brood size, suggesting some particular importance of this prey in the goshawk diet. In all, diet seemed to explain partly betweenlandscape variations in the brood size of the goshawk. The brood size was significantly higher in the urban landscape than elsewhere.
Irruptive migrants often show biased sex and age ratio, and typically young females are the most abundant class participating in irruptions. Several hypotheses have been proposed to explain differential migration in birds. We examined these hypotheses in a sexually size‐dimorphic species (females being larger than males), the pygmy owl Glaucidium passerinum, whose migration behaviour has also been poorly documented. Migration data were collected at the Hanko Bird Observatory, SW Finland during 1979–2010. Pygmy owls showed large fluctuations in migration numbers between years. Most of the migrants were young birds and females migrated in larger numbers than males. Results support the ‘territory defence hypothesis’ since males showed weaker tendency to migrate despite the smaller body size, but the ‘dominance hypothesis’ was also supported (subordinate young outnumber dominant adults in migration numbers). Findings support the idea that in owl species, which are dependent on nesting cavities, males show lower migration behaviour than females, whereas the pattern is opposite in species which normally breed outside cavities. In addition, adults migrated later than young, likely because they need to moult remiges before departure. Early hatched young also migrated earlier than late hatched young, suggesting that more dominant young migrate first.
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