POLYMORPHISM OF THE MOUSE E2A GENE DUE TO AN INTRONIC DELETION OF 536BP

Examination of genetic polymorphism of the transcription factor-encodi ng gene E2A in laboratory and wild mice by Southern blotting has revea led the presence of two alleles. The most frequent allele is found in Mus musculus (Mm) musculus, as well. as Mm domesticus. The less common allele is restricted to the Mm domesticus subspecies. Characterisatio n of these alleles has shown that the less common allele contains a de letion of approx. 500 bp located within a 1.8-kb intron immediately up stream from the E12 basic helix-loop-helix exon. DNA sequencing determ ined the deletion to span 536 bp including nucleotides 1045-1580 of th e intron within the common allele. The deleted region includes several sequences with similarity to gene regulatory motifs; however, express ion of E12 and intron splicing appear unaltered. The occurrence of an identical deletion in mice from different geographical regions suggest s that the uncommon allele may have a long evolutionary history.