10 research outputs found

    Diversity of lactase persistence in African milk drinkers

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    The genetic trait of lactase persistence is attributable to allelic variants in an enhancer region upstream of the lactase gene, LCT. To date, five different functional alleles, -13910*T, -13907*G, -13915*G, -14009*G and -14010*C, have been identified. The co-occurrence of several of these alleles in Ethiopian lactose digesters leads to a pattern of sequence diversity characteristic of a 'soft selective sweep'. Here we hypothesise that throughout Africa, where multiple functional alleles co-exist, the enhancer diversity will be greater in groups who are traditional milk drinkers than in non-milk drinkers, as the result of this sort of parallel selection. Samples from 23 distinct groups from 10 different countries were examined. Each group was classified 'Yes 'or 'No' for milk-drinking, and ethnicity, language spoken and geographic location were recorded. Predicted lactase persistence frequency and enhancer diversity were, as hypothesised, higher in the milk drinkers than the non-milk-drinkers, but this was almost entirely accounted for by the Afro-Asiatic language speaking peoples of east Africa. The聽other groups, including the 'Nilo-Saharan language speaking' milk-drinkers, show lower frequencies of LP and lower diversity, and there was a north-east to south-west decline in overall diversity. Amongst the Afro-Asiatic (Cushitic) language speaking Oromo, however,聽the geographic cline was not evident and the southern pastoralist Borana showed much higher LP frequency and enhancer diversity than the other groups. Together these results reflect the effects of parallel selection, the stochastic processes of the occurrence and spread of the mutations, and time depth of milk drinking tradition

    Assesment of norway spruce health using multispectral images acquired from unmanned aerial vehicle with non-metric cameras

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    W pracy oceniono przydatno艣膰 zdj臋膰 w zakresie bliskiej podczerwieni. Zdj臋cia wykonano zmodyfikowanymi aparatami cyfrowymi (Sigma DP2) zamontowanymi na bezza艂ogowym statku lataj膮cym AVI-1. Dla wybranego obiektu badawczego o pow. 284 ha, wykonano 930 zdj臋膰 o rozdzielczo艣ci terenowej 0,15 m. Zdj臋cia zosta艂y przetworzone do postaci ortomozaik w barwach naturalnych oraz zbli偶onych do spektrostrefowych. W terenie wykonano obserwacje koron 艣wierk贸w rosn膮cych w ok. 40-letnim, jednogatunkowym drzewostanie. Okre艣lono g臋sto艣膰 igliwia, jego kolor oraz inne symptomy 艣wiadcz膮ce o kondycji drzew. Te same drzewa zidentyfikowano na ortomozaikach i poddano klasyfikacji, kt贸rej wyniki por贸wnano z danymi uzyskanymi w terenie. Ocen臋 stanu zdrowotnego 艣wierka (Picea bies) na ortomozaikach wykonano analizuj膮c udzia艂 barwy czerwonej zwi膮zanej z r贸偶nymi objawami chorobowymi i uszkodze艅 koron. Obserwacje wykona艂o niezale偶nie od siebie dw贸ch obserwator贸w, ka偶dy w dw贸ch seriach. Ocen臋 jednolito艣ci rozpoznawania barw przez obserwator贸w oparto na por贸wnaniu uzyskanych warto艣ci. Stwierdzono, 偶e jest mo偶liwe podzielenie obserwowanych drzew na kilka klas zdrowotno艣ci.Several tests were carried out of unmanned aerial vehicles (UAV) equipped with customer cameras to take pictures of forest areas. Based on this a special own UAV was built which can carry a set of non-metric digital cameras recording images in RGB and near-IR channels. Approximately 1000 aerial images with a ground resolution of 0.15 m were taken for the selected research facility with an area of approximately 250 ha. These images were used to produce an orthomosaic in natural and multispectral bands. It was decided to find out whether it is possible to evaluate the health condition of spruce (Picea abies). The field observations were made of the crowns of spruces growing in about 40-year-old single-species stand. Information on the density of pine needles, its color, and other symptoms of the tree condition were recorded. The same trees were identified on orthomosaic and classified. Results of classification from the field and orthomosaic were compared. It was concluded, that it is possible to divide the observed number of trees into several health condition classes
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