Identification and ranking of genetic and laboratory environment factors influencing a behavioral trait, thermal nociception, via computational analysis of a large data archive

• Published in: Neuroscience and Biobehavioral Reviews Vol. 26; no. 8; pp. 907 - 923
• Main Authors: Chesler, Elissa J, Wilson, Sonya G, Lariviere, William R, Rodriguez-Zas, Sandra L, Mogil, Jeffrey S
• Format: Book Review Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 01-12-2002; Elsevier
• Subjects: Animals; Archives; Automatic Data Processing; Behavior - physiology; Biological and medical sciences; CART; Computational Biology; Data mining; Environment; Female; Fundamental and applied biological sciences. Psychology; Genetic; Genetics; Genotype; Laboratories; Male; Mice; Mice, Inbred Strains; Models, Genetic; Nociception; Pain; Pain Measurement; Perception; Proprioception. Interoception. Pain perception; Psychology. Psychoanalysis. Psychiatry; Psychology. Psychophysiology; Quantitative Trait, Heritable; Seasons; Species Specificity; Nociception; Pain; Genetic; Environment; Mice; Data mining; CART; Noxious stimulus; Methodology; Rodentia; Thermal stimulus; Environmental factor; Review; Genetic determinism; Ambient humidity; Strain; Vertebrata; Mammalia; Investigation method; Mouse; Animal; Sexual dimorphism; Comparative study
• ISSN: 0149-7634; 1873-7528
• DOI: 10.1016/S0149-7634(02)00103-3

Laboratory conditions in biobehavioral experiments are commonly assumed to be ‘controlled’, having little impact on the outcome. However, recent studies have illustrated that the laboratory environment has a robust effect on behavioral traits. Given that environmental factors can interact with trait-relevant genes, some have questioned the reliability and generalizability of behavior genetic research designed to identify those genes. This problem might be alleviated by the identification of the most relevant environmental factors, but the task is hindered by the large number of factors that typically vary between and within laboratories. We used a computational approach to retrospectively identify and rank sources of variability in nociceptive responses as they occurred in a typical research laboratory over several years. A machine-learning algorithm was applied to an archival data set of 8034 independent observations of baseline thermal nociceptive sensitivity. This analysis revealed that a factor even more important than mouse genotype was the experimenter performing the test, and that nociception can be affected by many additional laboratory factors including season/humidity, cage density, time of day, sex and within-cage order of testing. The results were confirmed by linear modeling in a subset of the data, and in confirmatory experiments, in which we were able to partition the variance of this complex trait among genetic (27%), environmental (42%) and genetic×environmental (18%) sources.