Susceptibility of chimera mice to epileptic convulsion

The ddY mouse-derived E1 strain is a mutant susceptible to severe epileptic convulsion. Using a method of aggregation of embryos from the F1 progenies of ddY female X El male and ddY female X C57BL/6J male, seven chimera mice were produced. These seven chimera mice manifested distribution of white coat color derived from F1 progeny of ddY X El, in two 100%, one 50%, two 24%, and two less than 4% and the frequency of the seizure occurrence were 71.4%, 50%, 28.6%, 28.6%, 21.4%, 0.7% and 0%, respectively. It was found that the chimera mouse which had a larger percent of white coat color had higher susceptibility to epileptic convulsion, the susceptibility having been proportional to the degree of the tissue mosaicism.