Epistatic interactions of genes influence withini

Authors: Larry J Leamy Daniel Pomp J Timothy Lightfoot

Publish Date: 2011/06/11

Volume: 139, Issue: 6, Pages: 813-821

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Abstract

A number of quantitative trait loci QTLs recently have been discovered that affect various activity traits in mice but their collective impact does not appear to explain the consistently moderate to high heritabilities for these traits We previously suggested interactions of genes or epistasis might account for additional genetic variability of activity and tested this for the average distance duration and speed run by mice during a 3 week period We found abundant evidence for epistasis affecting these traits although recognized that epistatic effects may well vary within individuals over time We therefore conducted a full genome scan for epistatic interactions affecting these traits in each of seven threeday intervals Our intent was to assess the extent and trends in epistasis affecting these traits in each of the intervals We discovered a number of epistatic interactions of QTLs that influenced the activity traits in the mice the majority of which were not previously found and appeared to affect the activity traits especially distance and speed primarily in the early or in the late age intervals The overall impact of epistasis was considerable its contribution to the total phenotypic variance varying from an average of 22–35 in the three traits across all age intervals It was concluded that epistasis is more important than singlelocus effects of genes on activity traits at specific ages and it is therefore an essential component of the genetic architecture of physical activityWe should like to thank two anonymous reviewers for excellent revision suggestions on an earlier version of this paper This work was supported in part by grants from the National Institutes of Health NIDDK DK61635 to J Timothy Lightfoot NIAMS AR050085 to J Timothy Lightfoot and Larry J Leamy and NIDDK DK076050 to Daniel Pomp

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