Spatial analysis of within-population microsatellite variability reveals restricted gene flow in the Pacific golden chanterelle (Cantharellus formosus).
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We examined the within-population genetic structure of the Pacific golden chanterelle (Cantharellus formosus) in a 50 y old forest stand dominated by Douglas-fir (Pseudotsuga menziesii) and western hemlock (Tsuga heterophylla) with spatial autocorrelation analysis. We tested the null hypothesis that multilocus genotypes possessed by chanterelle genets were randomly distributed within the study area. Fruit bodies from 203 C. formosus genets were collected from a 50 ha study plot. One hundred six unique multilocus genotypes were identified after scoring these collections at five microsatellite loci. Statistically significant positive spatial autocorrelation was detected indicating the presence of fine-scale genetic structure within the area. Repeated autocorrelation analyses with varied minimum distance classes (50-500 m) detected positive spatial genetic structure up to 400 m. Therefore nonrandom evolutionary processes (e.g., isolation by distance) can cause fine-scale genetic structure in C. formosus. The implications of this research for future broad-scale population studies of this species are that population samples should be separated by at least 400 m to be considered statistically independent. Sampling designs that account for fine-scale genetic structure will better characterize heterogeneity distributed across the landscape by avoiding the effects of pseudo replication. (+info)
Mineral waters, electricity, and hemlock: devising therapeutics for children in eighteenth-century institutions.
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Water hemlock (Cicuta douglasii) toxicoses in sheep: pathologic description and prevention of lesions and death.
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Water hemlock causes numerous livestock losses in North America every year. Description of pathologic and serum biochemical changes has been lacking in the literature. Tubers of western water hemlock (Cicuta douglasii) induced excessive salivation, tremors, grand mal seizures, skeletal and cardiac myodegeneration, and death in sheep given 1.2-2.7 g fresh tuber/kg body weight by gavage. Seizures were intermittent with periods of relaxation until death occurred from anoxia during seizure activity. In sheep given 1.5-2.5 times the lethal dose of water hemlock by gavage, intravenous administration of sodium pentobarbital at the onset of the first seizure prevented further seizure activity and skeletal and cardiac myodegeneration and resulted in rapid and complete recovery. (+info)