We tested the hypothesis that Bis1, a gene involved in seizure regulation in mice which has been localized to the distal part of chromosome 4, was the same as the gene Kcnab2, encoding the beta2-subunit for voltage-dependent K+ channels. Two facts suggested this hypothesis: Kcnab2 is located in the 3.1-cM confidence interval containing Bis1 and many studies have shown an involvement of K+ channels in the genesis of seizures. DNA sequence analysis of the coding sequence for Kcnab2 from JE/Le mice revealed no structural alterations which might affect Kcnab2 function. However, several nucleotide changes were observed.