Identity of homozygous or heterozygous fad2 mice. (A) Schematic diagram of the primer positions indicating the fragments spanning the 3' integration site in wild-type C57 or transgene-specific fragments in fad2 mice. (B) Site-specific primers used to identify fad2 homozygotes and heterozygotes. C57 samples had the 495-bp product only, fad2 males (X+Y) and homozygous females (X+X+) had the 567-bp transgene products only, and the heterozygous fad2 females (X+X) had both bands together. X+ and X represent the X chromosome integrated with fad2 transgene and wild-type X chromosome, respectively.