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- Eeva, Tapio, et al.
(författare)
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Species and abundance of ectoparasitic flies (Diptera) in pied flycatcher nests in Fennoscandia
- 2015
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Ingår i: Parasites & Vectors. - : BioMed Central. - 1756-3305. ; 8
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Tidskriftsartikel (refereegranskat)abstract
- Background: Birds host several ectoparasitic fly species with negative effects on nestling health and reproductive output, and with the capability of transmitting avian blood parasites. Information on the abundance and distribution of the ectoparasitic fly genera Ornithomya (Hippoboscidae) and Protocalliphora (Calliphoridae) in northern Europe is still generally poor, and we thus explored their geographic range and occurrence of these flies in the nests of a common avian model species, the pied flycatcher Ficedula hypoleuca. Methods: Nests of F. hypoleuca were collected from 21 locations across Fennoscandia in summer 2013, across a latitudinal gradient (between 56 degrees N - 70 degrees N) and examined for the presence of fly puparia. Adult specimens of Ornithomya spp. were also collected for species identification. Fly species were identified morphologically and identifications confirmed with DNA barcoding. Results: We found three species: two louse-flies - Ornithomya chloropus and O. avicularia - and one blow-fly, Protocalliphora azurea. The prevalence of O. avicularia was higher in southern latitudes and this species was not encountered beyond 62 degrees N whereas O. chloropus and P. azurea occurred across the whole range of latitudes. The prevalence of O. chloropus further increased with increasing distance from the coast - a pattern not documented before. The three fly species showed no interspecific associations in their prevalence. Conclusions: Our study revealed relatively high prevalence for all the species (O. chloropus 59 %, O. avicularia 20 %, P. azurea 32 %), and an interesting spatial pattern in the prevalence of the two louse fly species. Our sample did not indicate any major range shifts towards the north for the southern species as compared to the information from the past. Morphological identification of O. chloropus did not match with the corresponding sequences published in the GenBank and taxonomy of this group calls for further studies.
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| 2. |
- Joshi, Peter K, et al.
(författare)
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Directional dominance on stature and cognition in diverse human populations
- 2015
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Ingår i: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 523:7561, s. 459-462
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Tidskriftsartikel (refereegranskat)abstract
- Homozygosity has long been associated with rare, often devastating, Mendelian disorders, and Darwin was one of the first to recognize that inbreeding reduces evolutionary fitness. However, the effect of the more distant parental relatedness that is common in modern human populations is less well understood. Genomic data now allow us to investigate the effects of homozygosity on traits of public health importance by observing contiguous homozygous segments (runs of homozygosity), which are inferred to be homozygous along their complete length. Given the low levels of genome-wide homozygosity prevalent in most human populations, information is required on very large numbers of people to provide sufficient power. Here we use runs of homozygosity to study 16 health-related quantitative traits in 354,224 individuals from 102 cohorts, and find statistically significant associations between summed runs of homozygosity and four complex traits: height, forced expiratory lung volume in one second, general cognitive ability and educational attainment (P < 1 × 10(-300), 2.1 × 10(-6), 2.5 × 10(-10) and 1.8 × 10(-10), respectively). In each case, increased homozygosity was associated with decreased trait value, equivalent to the offspring of first cousins being 1.2 cm shorter and having 10 months' less education. Similar effect sizes were found across four continental groups and populations with different degrees of genome-wide homozygosity, providing evidence that homozygosity, rather than confounding, directly contributes to phenotypic variance. Contrary to earlier reports in substantially smaller samples, no evidence was seen of an influence of genome-wide homozygosity on blood pressure and low density lipoprotein cholesterol, or ten other cardio-metabolic traits. Since directional dominance is predicted for traits under directional evolutionary selection, this study provides evidence that increased stature and cognitive function have been positively selected in human evolution, whereas many important risk factors for late-onset complex diseases may not have been.
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