A simplified triple-test cross analysis of alcohol preference in the rat

Reanalyses of first-degree biometrical genetic data from previous studies of alcohol preference in the mouse revealed little consistency beyond a basic additive genetic component. A simplified triple-test cross in the rat investigated the genetic architecture of alcohol preference for a 10% (w/v) alcohol solution or water. An initial survey of eight selected and inbred strains identified high- and low-scoring strains, the MNR and the ACI, respectively, which were crossed as tester lines to six strains (the RHA, RLA, TMB, TMD, MNR, and ACI) to produce the required set of largely F₁ families. The additive-dominance model proved adequate for males, and directional dominance for low alcohol preference was found on all three measures: alcohol intake, alcohol preference ratio, and alcohol calorie contribution ratio. For females the model was adequate only for alcohol preference ratio, which showed ambidirectional dominance. The relevance of such genetic architecture to an animal model of alcoholism and to the evolution of alcohol drinking in the rat is discussed.This work was supported by a grant from the Medical Research Council of Great Britain to Professor J. L. Jinks and the second author and by a postgraduate studentship from the council to the first author.