Figure 2.

Southern blot analysis of EcoRI-digested genomic DNA following the crossing of male and female heterozygote mice. DNA was extracted from (Upper) tails of 3-week-old littermates or (Lower) tails and limbs of littermate embryos at E13. Blots were hybridized with a 5′ flanking probe. Wild-type and mutant allele correspond to 25 and 17.5 kb fragments, respectively.