Genetic structure of hereditary catalepsy in mice

Catalepsy or pronounced freezing is a natural passive defense strategy in animals and a syndrome of some mental disorders in human. Hereditary catalepsy was shown to be associated with depressive-like features in rats and mice. The loci underlying the difference in predisposition to catalepsy between catalepsy-prone CBA/lacJ and catalepsy-resistant AKR/J mice were mapped using congenic line and selective breeding approaches. Three congenic mouse lines (AKR.CBA-D13Mit76C, AKR.CBA-D13Mit76A and AKR.CBA-D13Mit78) carrying the 59- to 70-, 61- to 70- and 71- to 75-cM fragments of chromosome 13 transferred from the CBA to the AKR genome were created by nine successive backcrossing of (CBA x AKR)F-1 on AKR strain. Because catalepsy was found only in the AKR.CBA-D13Mit76C and AKR.CBA-D13Mit76A mice, the major gene of catalepsy was mapped on the fragment of 61-70 cM. Selective breeding of the (CBA x (CBA x AKR))BC backcross generation for high predisposition to catalepsy showed numerous genome-wide distributed CBA-derived alleles as well as the AKR-derived alleles mapped on chromosome 17 and on the proximal parts of chromosomes 10 and 19 that increased the cataleptogenic effect of the major gene.