Inheritance of reaction to halothane anaesthesia in pigs

SUMMARY The inheritance of reaction to halothane anaesthesia (so-called malignant hyperthermia syndrome) in pigs was studied in a series of 61 litters by 18 sires from an F3–F4 Pietrain–Hampshire crossbred population. A single locus two allele model allowing for reactors from all three genotypes, was fitted by maximum likelihood. It was concluded that the reaction is due to a single autosomal recessive gene with a frequency of 0·46 (0·44–0·48) and penetrance of 0·95 (0·92–0·98) in this stock.