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Significant Genetic Variation (significant + genetic_variation)
Selected AbstractsStrain-dependent regulation of neurotransmission and actin-remodelling proteins in the mouse hippocampusGENES, BRAIN AND BEHAVIOR, Issue 2 2006D. D. Pollak Individual mouse strains differ significantly in terms of behaviour, cognitive function and long-term potentiation. Hippocampal gene expression profiling of eight different mouse strains points towards strain-specific regulation of genes involved in neuronal information storage. Protein expression with regard to strain- dependent expression of structures related to neuronal information storage has not been investigated yet. Herein, a proteomic approach based on two-dimensional gel electrophoresis coupled with mass spectrometry (MALDI-TOF/TOF) has been chosen to address this question by determining strain-dependent expression of proteins involved in neurotransmission and activity-induced actin remodelling in hippocampal tissue of five mouse strains. Of 31 spots representing 16 different gene products analysed and quantified, N -ethylmaleimide-sensitive fusion protein, N -ethylmaleimide-sensitive factor attachment protein-,, actin-like protein 3, profilin and cofilin were expressed in a strain-dependent manner. By treating protein expression as a phenotype, we have shown significant genetic variation in brain protein expression. Further experiments in this direction may provide an indication of the genetic elements that contribute to the phenotypic differences between the selected strains through the expressional level of the translated protein. In view of this, we propose that proteomic analysis enabling to concomitantly survey the expression of a large number of proteins could serve as a valuable tool for genetic and physiological studies of central nervous system function. [source] Direct and correlated responses to selection on age at physiological maturity in Drosophila simulansJOURNAL OF EVOLUTIONARY BIOLOGY, Issue 6 2000D. E. L. Promislow Biologists who study the timing of development in insects have focused on variation in duration of pre-adult stages almost without exception. However, development is not complete until adults are not only morphologically mature, but also reproductively mature. Here we describe an experiment in the fruit fly, Drosophila simulans, in which we used artificial selection to create lines with shortened and lengthened duration from eclosion to the age when the first egg was laid. We found significant genetic variation for this trait. The response to selection on age when the first egg was laid was due to variation among females. Delayed adult development was correlated with rapid pre-adult development and longer life span in females. The approach we use here resolves some difficulties with previous approaches used to study the genetics of senescence, and provides an opportunity to study the hitherto unexamined predictions derived from classic models for the evolution of senescence. [source] Baculovirus expression of erythrovirus V9 capsids and screening by ELISA: Serologic cross-reactivity with erythrovirus B19JOURNAL OF MEDICAL VIROLOGY, Issue 2 2002Erik D. Heegaard Abstract Diagnosis of erythrovirus B19 (B19) relies on serology and the detection of viral DNA. Recently, a distinct erythrovirus isolate termed V9, markedly different from erythrovirus B19 (>,11% nucleotide disparity), was isolated. Standard B19 PCR assays were inconclusive and serologic tests failed to categorize V9 as an acute B19-like infection. Sequencing, combined with PCR studies, have since demonstrated the need for specific and differentiated techniques when examining samples for possible B19 or V9 viremia. The antigenic properties of the V9 capsid proteins have not been characterized previously. To address this question, V9 VP1 and VP2 open reading frames were cloned and expressed in insect cells using a baculovirus vector. Large quantities of purified recombinant V9 capsid protein were produced and electron micrographs revealed self-assembly of V9 VP1/VP2 and VP2 capsids into empty icosahedral erythrovirus-like particles with a diameter of ,23 nm. Screening of a panel of 270 clinical samples for the presence of V9 IgM and IgG antibodies in ELISA showed 100% serologic cross-reactivity between B19 and V9 when comparing V9 VP2 capsids to a commercial B19 VP2 assay. This suggests that both a V9 and a B19 antibody response may be diagnosed equally well by ELISA using either V9 or B19 recombinant capsids as antigen source. Retrospectively, translation of the V9 sequence indicates that despite a significant genetic variation on the DNA level, the majority of the discrepant DNA sequence represents silent mutations leading to an amino acid sequence very similar to the known B19 strains (96,97% homology). J. Med. Virol. 66:246,252, 2002. © 2002 Wiley-Liss, Inc. [source] Tolerance to apical and foliar damage: costs and mechanisms in Raphanus raphanistrumOIKOS, Issue 12 2007Elin Boalt To study mechanisms underlying plant tolerance to herbivore damage, we used apical and foliar damage as experimental treatments to study whether there are similar tolerance mechanisms to different types of damage. We also studied whether tolerance to different types of damage are associated, and whether there is a cost involved in plant tolerance to different types of herbivore damage. Our greenhouse experiment involved 480 plants from 30 full-sib families of an annual weed Raphanus raphanistrum, wild radish, which were subjected to control and two different simulated herbivore damage treatments, apex removal and foliar damage of 30% of leaf area. Apical damage significantly decreased seed production, whereas foliar damage had no effect. There was a significant genetic variation for tolerance to foliar, but not apical damage. No costs were observed in terms of negative correlation between tolerance to either damage type and fitness of undamaged plants. Tolerances to apical and foliar damage were not significantly correlated with each other. We observed a larger number of significant associations between tolerance and reproductive traits than between tolerance and vegetative traits. Plant height and leaf size of damaged plants interacted in their association to tolerance to foliar damage. Inflorescence number and pollen quantity per flower of damaged plants were positively associated with tolerance to apical damage. In late-flowering genotypes, petal size of undamaged plants and pollen quantity of damaged plants were positively associated with tolerance to foliar damage. In summary, traits involved in floral display and male fitness were associated with plant tolerance to herbivore damage. [source] | ||||||||||