Colorectal cancer - Demand for a joint Nordic study on the value of colonoscopic screening

To access publisher full text version of this article. Please click on the hyperlink in Additional Links fieldNo abstract availabl

Comprehensive population-wide analysis of Lynch syndrome in Iceland reveals founder mutations in MSH6 and PMS2.

To access publisher's full text version of this article, please click on the hyperlink in Additional Links field or click on the hyperlink at the top of the page marked FilesLynch syndrome, caused by germline mutations in the mismatch repair genes, is associated with increased cancer risk. Here using a large whole-genome sequencing data bank, cancer registry and colorectal tumour bank we determine the prevalence of Lynch syndrome, associated cancer risks and pathogenicity of several variants in the Icelandic population. We use colorectal cancer samples from 1,182 patients diagnosed between 2000-2009. One-hundred and thirty-two (11.2%) tumours are mismatch repair deficient per immunohistochemistry. Twenty-one (1.8%) have Lynch syndrome while 106 (9.0%) have somatic hypermethylation or mutations in the mismatch repair genes. The population prevalence of Lynch syndrome is 0.442%. We discover a translocation disrupting MLH1 and three mutations in MSH6 and PMS2 that increase endometrial, colorectal, brain and ovarian cancer risk. We find thirteen mismatch repair variants of uncertain significance that are not associated with cancer risk. We find that founder mutations in MSH6 and PMS2 prevail in Iceland unlike most other populations.Ohio State University (OSU) Comprehensive Cancer Center OSU Colorectal Cancer Research fund Obrine-Weaver Fund Pelotonia Fellowship Award deCODE genetic

Data from: Local adaptation and evolutionary potential along a temperature gradient in the fungal pathogen Rhynchosporium commune

To predict the response of plant pathogens to climate warming, data are needed on current thermal adaptation, the pathogen’s evolutionary potential and the link between them. We conducted a common garden experiment using isolates of the fungal pathogen Rhynchosporium commune from nine barley populations representing climatically diverse locations. Clonal replicates of 126 genetically distinct isolates were assessed for their growth rate at 12°C, 18°C and 22°C. Populations originating from climates with higher monthly temperature variation had higher growth rate at all three temperatures compared to populations from climates with less temperature fluctuation. Population differentiation in growth rate (Q_ST) was significantly higher at 22°C than population differentiation for neutral microsatellite loci (G_ST), consistent with local adaptation for growth at higher temperatures. At 18°C we found evidence for stabilizing selection for growth rate as Q_ST was significantly lower than G_ST. Heritability of growth rate under the three temperatures was substantial in all populations (0.58-0.76). Genetic variation was lower in populations with higher growth rate at the three temperatures and evolvability increased under heat stress in seven out of nine populations. Our findings imply that the distribution of this pathogen is unlikely to be genetically limited under climate warming, due to its high genetic variation and plasticity for thermal tolerance

The influence of genetic drift and selection on quantitative traits in a plant pathogenic fungus

Genetic drift and selection are ubiquitous evolutionary forces acting to shape genetic variation in populations. While their relative importance has been well studied in plants and animals, less is known about their relative importance in fungal pathogens. Because agro-ecosystems are more homogeneous environments than natural ecosystems, stabilizing selection may play a stronger role than genetic drift or diversifying selection in shaping genetic variation among populations of fungal pathogens in agro-ecosystems. We tested this hypothesis by conducting a QST/FST analysis using agricultural populations of the barley pathogen Rhynchosporium commune. Population divergence for eight quantitative traits (QST) was compared with divergence at eight neutral microsatellite loci (FST) for 126 pathogen strains originating from nine globally distributed field populations to infer the effects of genetic drift and types of selection acting on each trait. Our analyses indicated that five of the eight traits had QST values significantly lower than FST, consistent with stabilizing selection, whereas one trait, growth under heat stress (22°C), showed evidence of diversifying selection and local adaptation (QST>FST). Estimates of heritability were high for all traits (means ranging between 0.55–0.84), and average heritability across traits was negatively correlated with microsatellite gene diversity. Some trait pairs were genetically correlated and there was significant evidence for a trade-off between spore size and spore number, and between melanization and growth under benign temperature. Our findings indicate that many ecologically and agriculturally important traits are under stabilizing selection in R. commune and that high within-population genetic variation is maintained for these traits.ISSN:1932-620

Raw data Dryad

Growth rate data in mm/day for all temperatures, populations, isolates and replicates

Local adaptation and evolutionary potential along a temperature gradient in the fungal pathogen Rhynchosporium commune

To predict the response of plant pathogens to climate warming, data are needed on current thermal adaptation, the pathogen's evolutionary potential, and the link between them. We conducted a common garden experiment using isolates of the fungal pathogen Rhynchosporium commune from nine barley populations representing climatically diverse locations. Clonal replicates of 126 genetically distinct isolates were assessed for their growth rate at 12°C, 18°C, and 22°C. Populations originating from climates with higher monthly temperature variation had higher growth rate at all three temperatures compared with populations from climates with less temperature fluctuation. Population differentiation in growth rate (QST) was significantly higher at 22°C than population differentiation for neutral microsatellite loci (GST), consistent with local adaptation for growth at higher temperatures. At 18°C, we found evidence for stabilizing selection for growth rate as QST was significantly lower than GST. Heritability of growth rate under the three temperatures was substantial in all populations (0.58–0.76). Genetic variation was lower in populations with higher growth rate at the three temperatures and evolvability increased under heat stress in seven of nine populations. Our findings imply that the distribution of this pathogen is unlikely to be genetically limited under climate warming, due to its high genetic variation and plasticity for thermal tolerance.ISSN:1752-4571ISSN:1752-456

The influence of genetic drift and selection on quantitative traits in a plant pathogenic fungus

Genetic drift and selection are ubiquitous evolutionary forces acting to shape genetic variation in populations. While their relative importance has been well studied in plants and animals, less is known about their relative importance in fungal pathogens. Because agro-ecosystems are more homogeneous environments than natural ecosystems, stabilizing selection may play a stronger role than genetic drift or diversifying selection in shaping genetic variation among populations of fungal pathogens in agro-ecosystems. We tested this hypothesis by conducting a QST/FST analysis using agricultural populations of the barley pathogen Rhynchosporium commune. Population divergence for eight quantitative traits (QST) was compared with divergence at eight neutral microsatellite loci (FST) for 126 pathogen strains originating from nine globally distributed field populations to infer the effects of genetic drift and types of selection acting on each trait. Our analyses indicated that five of the eight traits had QST values significantly lower than FST, consistent with stabilizing selection, whereas one trait, growth under heat stress (22°C), showed evidence of diversifying selection and local adaptation (QST>FST). Estimates of heritability were high for all traits (means ranging between 0.55–0.84), and average heritability across traits was negatively correlated with microsatellite gene diversity. Some trait pairs were genetically correlated and there was significant evidence for a trade-off between spore size and spore number, and between melanization and growth under benign temperature. Our findings indicate that many ecologically and agriculturally important traits are under stabilizing selection in R. commune and that high within-population genetic variation is maintained for these traits.ISSN:1932-620

The genetic diversity of Icelandic populations of two barley leaf pathogens, Rhynchosporium commune and Pyrenophora teres

v2012o

DRYAD - All traits raw data_140912

Trait values of replicates of 14 isolates of each of nine Rhynchosporium commune populations. The eight quantitative traits studied were: growth rate at 12°C, growth rate at 18°C, growth rate at 22°C, fungicide resistance, melanization, spore size, spore number, and virulence

Comparison of genetic divergence estimated by <i>F</i>_ST and by <i>Q</i>_ST for eight quantitative traits of populations of <i>Rhynchosporium commune</i>.

<p><i>Q</i>_ST values were statistically different from <i>F</i>_ST except for growth rate at 12°C and fungicide resistance. Bars represent the 95% confidence interval. The range within the two dashed lines indicates the 95% confidence interval of overall <i>F</i>_ST. Traits with <i>Q</i>_ST below that range are interpreted as being under stabilizing selection, while traits with <i>Q</i>_ST above that range are interpreted as being under diversifying selection. When <i>Q</i>_ST and its confidence interval overlap with the <i>F</i>_ST range between the dashed lines, neutral evolution acting among populations cannot be excluded.</p