DISCOVERY OF A NEW POMC1 ALLELE IN THE LS X SS RECOMBINANT INBRED STRAINS - RELATIONSHIP TO LOCOMOTOR BEHAVIOR

Various lines of evidence suggest that a polymorphism in the gene for proopiomelanocortin, Pomc1, might account for some portion of the gene tic variance for open-field activity in the LS x SS RI strains. To tes t this hypothesis, approximately 1600 bp of Pomc1 was sequenced from g enomic DNA of seven of the LS x SS strains. Two distinct alleles conta ining a total of five single-base pair differences were detected, A su bstitution was found in the coding region causing a Pro-to-Ser convers ion, two substitutions occurred in the 3' untranslated region of the m RNA, and a substitution and a deletion were detected in the 3' untrans cribed flanking region. The fragment containing the coding region subs titution was sequenced in an additional 15 of the LS x SS strains. A t otal of 12 strains contained one form of the allele, while 10 had the other. The strain distribution pattern of open-field activity scores b etween the two alleles suggests that these alleles do not contribute t o the genetic variation of open-field activity in the LS x SS RI strai ns.