Open-field behavior in mice: A diallel analysis of selected lines.

The open-field behavior of 719 mice resulting from a diallel cross among the six lines of the DeFries selection experiment was assessed. Results of several analyses employing different models and procedures in open-field activity and defecation among these lines have predominantly additive effects. Estimates of heritability obtained from these analyses were considerably higher than previous estimates based on familial resemblance or the realized response to selection; thus estimation of heritability from diallel analyses is clearly unwarranted when selected lines are employed and the character of interest has been either directly or indirectly subjected to artificial selection.