A new genetic locus mapped from behavioral variation in mice: Audiogenic seizure prone (asp)

Audiogenic seizure susceptibility to the initial presentation of intense sound was studied in generations of mice derived from the susceptible DBA/2J and the resistant C57BL/6J inbred strains. The experimental results led to the detection, location, and position of a new genetic locus affecting behavior in mice. The locus is designatedasp (audiogenic seizure prone), and the pattern of inheritance for high seizure risk is recessive. Evidence for the mapping ofasp results from the following experimental findings: (1) frequencies of seizures for each of six segregating generations obtained by crossing C57BL/6J and DBA/2J conformed to expectations based upon a single locus model of genetic inheritance; (2) theasp-locus is loosely linked to theb-locus and thus resides on Linkage Group VIII of the mouse; (3) linkage relationships betweenasp and other named mutations on LG VIII, pintail (Pt),misty (m), brown (b), and autosomal glucose-6-phosphate dehydrogenase (Gpd-1), indicate that the position of theasp-locus is towards the centromeric end of the chromosome. The order of loci isasp-b-Pt-Gpd-1; (4) no linkage was observed betweenasp and thed-locus of Linkage Group II. These experiments illustrate that new genetic loci, whose allelic alternatives exert major effects on chosen behavioral characters, can be identified and mapped in a directed search.In memory of Dr. Margaret M. Dickie who died July 4, 1969. Supported by NIH Research Grant MH 11327 from the National Institute of Mental Health and partly by an allocation from the American Cancer Society Institutional grant IN-19 to the Jackson Laboratory. The principles of laboratory animal care as advocated by the National Society for Medical Research are observed in this laboratory.