All mice are not equal: effects of genetic and environmental variability on the reduction of phenotypic plasticity
Final Report Abstract
The mouse, including countless lines of transgenic and knockout mice, has become the most prominent model organism in biomedical research. Behavioural characterization is often conducted in batteries of short tests on locomotion, anxiety, learning and memory, etc. In such tests, any individual differences within groups are usually considered to be disturbing variance. Despite of an enormous efforts of standardization a considerable amount of inter-individual differences persist. In this project we demonstrate that individual differences can reasonably be discussed as 'animal personalities'. We are especially interested in how such these traits develop over the life time of individual mice since long term observations in mice are surprisingly rare. The experimental design includes female mice from two inbred strains and the progeny of intercrosses of the two strains up to the second filial generation. These mice are observed in their behavioural development over the course of 26 weeks. During this period of time three repeats of a behavioural test battery, analysis of stress hormones, constant activity monitoring, and an in depth automated behavioural characterization including tests for cognitive skills in IntelliCages are accomplished. The analysis of the large data set derived from these experiments is currently still being carried out. First results confirm animal personality like traits and individual differences that escape all efforts of standardisation. Furthermore, our data backs up strong parent-of-origin as well as early postnatal environment effects on the phenotypes later in life. Genetic diversity seems to increase the repeatability over time. Further analysis of gene and environmental contributions to the reduction of phenotypic plasticity is still being carried out. In a complementary approach we observed the behavioural development of male inbred mice from birth to death focussing on individual differences in relation to cognitive demands. To our knowledge this is the first time that mice are systematically observed throughout their entire life and this data will contribute significantly to the understanding of the reduction of phenotypic plasticity. Immer vorneweg! – Von Leithammeln und Alphatieren, Interview mit Lars Lewejohann in der SWR2 Matinee, 24.4.16, https://goo.gl/GYPFGe. Unerhört. Können sich Tiere unterhalten?, Beitrag von Lars Lewejohann zum 8. Osnabrücker Wissensforum 2015, https://goo.gl/5JiPMc. How does individuality develop?, Hannah Critchlow on "The Naked Scientists", 20.05.2013, https://goo.gl/UkW5Ae. Faulpelze, Angsthasen und schräge Vögel, Ina Schicker in Bild der Wissenschaft online 2011, https://goo.gl/OfCltp
Publications
- (2013): Emergence of Individuality in Genetically Identical Mice. Science 340: 756-759
Freund J, Brandmaier AM, Lewejohann L, Kirste I, Kritzler M, Krüger A, Sachser N, Lindenberger U, Kempermann G
(See online at https://doi.org/10.1126/science.1235294) - (2015): Association between exploratory activity and social individuality in genetically identical mice living in the same enriched environment. Neuroscience 309: 140-152
Freund, J; Brandmaier, AM; Lewejohann, L; Kirste, I; Kritzler, M; Krüger, A; Sachser, N; Lindenberger, U; Kempermann, G
(See online at https://doi.org/10.1016/j.neuroscience.2015.05.027) - (2015): Lifetime development of behavioural phenotype in the house mouse (Mus musculus). Frontiers in Zoology 12 (Suppl 1): 17
Brust, V; Schindler, PM; Lewejohann, L
(See online at https://doi.org/10.1186/1742-9994-12-S1-S17)
