Inheritance of pendulum movements in rats

: Inheritance of predisposition to pendulum movements (PMs) in rats was studied by two methods: segregation analysis of binary traits (on pedigrees recorded in the selection archives for cataleptic strain GC) and the classical Mendelian analysis of hybrids between strains PM+ and PM- selected for pronounced PMs and the absence of PMs, respectively. Both methods yields the same result: it was found that predisposition to PMs exhibited a monogenic dominant inheritance with incomplete penetrance.