Genetic variation for stress-response hormesis in C. elegans lifespan
Rodriguez Sanchez, M. ; Snoek, L.B. ; Riksen, J.A.G. ; Bevers, R.P.J. ; Kammenga, J.E. - \ 2012
Experimental Gerontology 47 (2012)8. - ISSN 0531-5565 - p. 581 - 587.
quantitative trait loci - genotype-environment interactions - nematode caenorhabditis-elegans - long-lived mutant - drosophila-melanogaster - heat-shock - history traits - natural variation - longevity - resistance
Increased lifespan can be associated with greater resistance to many different stressors, most notably thermal stress. Such hormetic effects have also been found in C. elegans where short-term exposure to heat lengthens the lifespan. Genetic investigations have been carried out using mutation perturbations in a single genotype, the wild type Bristol N2. Yet, induced mutations do not yield insight regarding the natural genetic variation of thermal tolerance and lifespan. We investigated the genetic variation of heat-shock recovery, i.e. hormetic effects on lifespan and associated quantitative trait loci (QTL) in C. elegans. Heat-shock resulted in an 18% lifespan increase in wild type CB4856 whereas N2 did not show a lifespan elongation. Using recombinant inbred lines (RILs) derived from a cross between wild types N2 and CB4856 we found natural variation in stress-response hormesis in lifespan. Approx. 28% of the RILs displayed a hormesis effect in lifespan. We did not find any hormesis effects for total offspring. Across the RILs there was no relation between lifespan and offspring. The ability to recover from heat-shock mapped to a significant QTL on chromosome II which overlapped with a QTL for offspring under heat-shock conditions. The QTL was confirmed by introgressing relatively small CB4856 regions into chromosome II of N2. Our observations show that there is natural variation in hormetic effects on C. elegans lifespan for heat-shock and that this variation is genetically determined.
A genome-wide library of CB4856/N2 introgression lines of Caenorhabditis elegans
Doroszuk, A. ; Snoek, L.B. ; Fradin, E. ; Riksen, J.A.G. ; Kammenga, J.E. - \ 2009
Nucleic acids research 37 (2009)16. - ISSN 0305-1048 - p. e110 - e110.
quantitative trait locus - life-history traits - genotype-environment interactions - natural variation - c-elegans - consomic strains - complex traits - qtl - architecture - polymorphism
Recombinant inbred lines (RILs) derived from Caenorhabditis elegans wild-type N2 and CB4856 are increasingly being used for mapping genes underlying complex traits. To speed up mapping and gene discovery, introgression lines (ILs) offer a powerful tool for more efficient QTL identification. We constructed a library of 90 ILs, each carrying a single homozygous CB4856 genomic segment introgressed into the genetic background of N2. The ILs were genotyped by 123 single-nucleotide polymorphism (SNP) markers. The proportion of the CB4856 segments in most lines does not exceed 3%, and together the introgressions cover 96% of the CB4856 genome. The value of the IL library was demonstrated by identifying novel loci underlying natural variation in two ageing-related traits, i.e. lifespan and pharyngeal pumping rate. Bin mapping of lifespan resulted in six QTLs, which all have a lifespan-shortening effect on the CB4856 allele. We found five QTLs for the decrease in pumping rate, of which four colocated with QTLs found for average lifespan. This suggests pleiotropic or closely linked QTL associated with lifespan and pumping rate. Overall, the presented IL library provides a versatile resource toward easier and efficient fine mapping and functional analyses of loci and genes underlying complex traits in C. elegans
Time for a shift in crop production: embracing complexity through diversity at all levels
Ostergard, H. ; Finckh, M.R. ; Fontaine, L. ; Goldringer, I. ; Hoad, S. ; Kristensen, K. ; Lammerts Van Bueren, E. ; Mascher, F. ; Munk, L. ; Wolfe, M.S. - \ 2009
Journal of the Science of Food and Agriculture 89 (2009)9. - ISSN 0022-5142 - p. 1439 - 1445.
earthworms aporrectodea-rosea - soil organic-matter - genotype-environment interactions - ecosystem services - wheat populations - powdery mildew - food security - agricultural sustainability - conservation tillage - carbon sequestration
A radical shift in our approach to crop production is needed to ensure food security and to address the problems of soil degradation, loss of biodiversity, polluted and restricted water supplies, coupled with a future of fossil fuel limitations and increasingly variable climatic conditions. An interdisciplinary network of European scientists put forward visions for future crop production embracing the complexity of our socio-ecological system by applying the principle of diversity at all levels from soil micro-organisms to plant varieties and cropping systems. This approach, integrated with careful deployment of our finite global resources and implementation of appropriate sustainable technology, appears to be the only way to ensure the scale of system resilience needed to cope with many of our concerns. We discuss some of the most important tools such as (i) building soil fertility by recycling of nutrients and sustainable use of other natural and physical resources, (ii) enhancing biological diversity by breeding of crops resilient to climate change and (iii) reconnecting all stakeholders in crop production. Finally, we emphasise some of the changes in agricultural and environmental regulation and policy needed in order to implement the visions.
Beyond induced mutants: using worms to study natural variation in genetic pathways
Kammenga, J.E. ; Philips, P.C. ; Bono, M. de; Doroszuk, A. - \ 2008
Trends in Genetics 24 (2008)4. - ISSN 0168-9525 - p. 178 - 185.
quantitative trait loci - life-history traits - genotype-environment interactions - single-nucleotide polymorphisms - nematode caenorhabditis-elegans - c-elegans - linkage disequilibrium - genus caenorhabditis - wild populations - expression
Induced mutants in the nematode Caenorhabditis elegans are used to study genetic pathways of processes ranging from aging to behavior. The effects of such mutations are usually analyzed in a single wildtype background: N2. However, studies in other species demonstrate that the phenotype(s) of induced mutations can vary widely depending on the genetic background. Moreover, induced mutations in one genetic background do not reveal the allelic effects that segregate in natural populations and contribute to phenotypic variation. Because other wildtype Caenorhabditis spp., including C. elegans, are now available, we review how current mapping resources and methodologies within and between species support the use of Caenorhabditis spp. for studying genetic variation, with a focus on pathways associated with human disease.
Effects of housing system (outdoor vs cages) and age of laying hens on egg characteristics
Brand, H. van den; Parmentier, H.K. ; Kemp, B. - \ 2004
British Poultry Science 45 (2004)6. - ISSN 0007-1668 - p. 745 - 752.
genotype-environment interactions - bone breaking strength - performance traits - albumin quality - layer lines - breeder age - phosphorus - calcium - storage - communication
1. Effects of two housing systems (cages vs outdoor) on external and internal egg characteristics were investigated. 2. In total 785 eggs from three different lines in cages and 268 eggs from outdoor-housed layers were examined for egg weight, albumen, yolk and shell content, albumen height and pH, and albumen and yolk dry matter content. 3. Interactions between layer age and housing systems were found for egg weight, eggshell content, albumen height, albumen pH, and dry matter content of the albumen and yolk. This was mainly due to the greater variation with age in the outdoor layers, compared to the caged layers. 4. Irrespective of age eggs from outdoor layers were relatively broader than eggs from the caged layers. Yolk colour was considerably darker in the outdoor group (11.0 vs 9.3). 5. We concluded that it is more difficult to maintain constant external and internal egg quality in an outdoor housing system than in a battery cage system. Factors that determine the greater fluctuations in internal egg quality need to be investigated.