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Université de Fribourg

Effects of inbreeding on aversive learning in Drosophila

Nepoux, V. ; Haag, Christoph R. ; Kawecki, Tadeusz J.

In: Journal of Evolutionary Biology, 2010, p. -

Inbreeding adversely affects life history traits as well as various other fitness-related traits, but its effect on cognitive traits remains largely unexplored, despite their importance to fitness of many animals under natural conditions. We studied the effects of inbreeding on aversive learning (avoidance of an odour previously associated with mechanical shock) in multiple inbred lines of...

Université de Fribourg

SV40-induced expression of calretinin protects mesothelial cells from asbestos cytotoxicity and may be a key factor contributing to mesothelioma pathogenesis

Henzi, Thomas ; Blum, Walter-Vincent ; Pfefferli, Martine ; Kawecki, Tadeusz J. ; Salicio, Valérie ; Schwaller, Beat

In: American Journal of Pathology, 2009, vol. 174, p. 2324-2336

The calcium-binding protein calretinin has emerged as a useful marker for the identification of mesotheliomas of the epithelioid and mixed types, but its putative role in tumor development has not been addressed previously. Although exposure to asbestos fibers is considered the main cause of mesothelioma, undoubtedly, not all mesothelioma patients have a history of asbestos exposure. The question...

Université de Fribourg

The influence of learning on evolution: a mathematical framework

Paenke, Ingo ; Kawecki, Tadeusz J. ; Sendhoff, Bernhard

In: Artificial Life, 2009, vol. 15, no. 2, p. 227-245

The Baldwin effect can be observed if phenotypic learning influences the evolutionary fitness of individuals, which can in turn accelerate or decelerate evolutionary change. Evidence for both learning-induced acceleration and deceleration can be found in the literature. Although the results for both outcomes were supported by specific mathematical or simulation models, no general predictions have...

Université de Fribourg

Life history consequences of adaptation to larval nutritional stress in Drosophila

Kolss, Munjong ; Vijendravarma, Roshan K. ; Schwaller, Geraldine ; Kawecki, Tadeusz J.

In: Evolution, 2009///doi: 10.1111/j.1558-5646.2009.00718.x

Many animal species face periods of chronic nutritional stress where the individuals must continue to develop, grow and/or reproduce despite low quantity or quality of food. Here we use experimental evolution to study adaptation to such chronic nutritional stress in six replicate Drosophila melanogaster populations selected for the ability to survive and develop within a limited time on a very...

Université de Fribourg

Heterozygosity of SNP513 in intron 9 of the human calretinin gene (CALB2) is a risk factor for colon cancer

Vonlanthen, Sivia ; Kawecki, Tadeusz J. ; Betticher, Daniel C. ; Pfefferli, Martine ; Schwaller, Beat

In: Anticancer Research, 2007, vol. 27, no. 6C, p. 4279-4288

BACKGROUND: The Ca2+-binding protein calretinin (CR), while absent in normal colonocytes, is expressed in the majority of poorly differentiated colon carcinomas, and is hypothesized that mutations in the distal part (from exon 7 to 10) of the CR gene (CALB2) could be responsible for the aberrant CR expression. MATERIALS AND METHODS: Using PCR amplification of genomic DNA and restriction...

Université de Fribourg

Learning ability and longevity: a symmetrical evolutionary trade-off in Drosophila

Burger, Joep M. S. ; Kolss, Munjong ; Pont, Juliette ; Kawecki, Tadeusz J.

In: Evolution, 2008, vol. 62, no. 6, p. 1294–1304

Learning ability can be substantially improved by artificial selection in animals ranging from Drosophila to rats. Thus these species have not used their evolutionary potential with respect to learning ability, despite intuitively expected and experimentally demonstrated adaptive advantages of learning. This suggests that learning is costly, but this notion has rarely been tested. Here we report...

Université de Fribourg

Reduced learning ability as a consequence of evolutionary adaptation to nutritional stress in Drosophila melanogaster

Kolss, Munjong ; Kawecki, Tadeusz J.

In: Ecological Entomology, 2008///doi:10.1111/j.1365-2311.2008.01007.x

Abstract. 1. Dietary conditions affect cognitive abilities of many species, but it is unclear to what extent this physiological effect translates into an evolutionary relationship.2. A reduction of competitive ability under nutritional stress has been reported as a correlated response to selection for learning ability in Drosophila melanogaster. Here we test whether the reverse holds as well,...

Université de Fribourg

Juvenile hormone as a regulator of the trade-off between reproduction and life span in Drosophila melanogaster

Flatt, Thomas ; Kawecki, Tadeusz J.

In: Evolution, 2007, vol. 61, no. 8, p. 1980–1991

Trade-offs between reproduction and life span are ubiquitous, but little is known about their underlying mechanisms. Here we combine treatment with the juvenile hormone analog (JHa) methoprene and experimental evolution in Drosophila melanogaster to study the potential role of juvenile hormone (JH) in mediating such trade-offs at both the physiological and evolutionary level. Exposure to...

Université de Fribourg

Influence of plasticity and learning on evolution under directional selection

Paenke, Ingo ; Sendhoff, Bernhard ; Kawecki, Tadeusz J.

In: American Naturalist, 2007, vol. 170, no. 2, p. E47-E58

Phenotypic plasticity and related processes (learning, developmental noise) have been proposed to both accelerate and slow down genetically based evolutionary change. While both views have been supported by various mathematical models and simulations, no general predictions have been offered as to when these alternative outcomes should occur. Here we propose a general framework to study the...

Université de Fribourg

Experimental evolution of olfactory memory in Drosophila melanogaster

Mery, Frederic ; Pont, Juliette ; Preat, Thomas ; Kawecki, Tadeusz J.

In: Physiological and Biochemical Zoology, 2007, vol. 80, no. 4, p. 399-405

In order to address the nature of genetic variation in learning performance, we investigated the response to classical olfactory conditioning in "high-learning" Drosophila melanogaster lines previously subject to selection for the ability to learn an association between the flavor of an oviposition medium and bitter taste. In a T-maze choice test, the seven high-learning lines were better at...