Mapping of a second recombination hot spot within the I-E region of the mouse H-2 gene complex.

The crossover points of nine intra-I region recombinant mouse strains were determined by restriction fragment analysis. The recombinants were examined for the presence of k and p haplotype specific DNA restriction endonuclease sites. These restriction sites were a Sac I site between the E beta and E beta 2 genes, a Hpa I site within the E beta 2 gene, and a Rsa I site approximately 1 kb to the right of the E alpha gene. Seven of the recombinants were found to have crossovers between the Hpa I and the Rsa I site. This analysis suggests that a recombination hot spot exists within this segment. This segment is approximately 12-14 kb, and contains the E alpha gene and the intervening sequence between the E beta 2 and E alpha genes.