Inguinal fat pad weight plotted versus body weight as a method of genotype identification in 16-day-old Zucker rats.

By plotting the weights of inguinal fat pad versus body weights in littermates from fa/fa X Fa/fa crosses, we observed that the data distributed along two widely separated regression lines as of 16 days of age. This procedure enabled us to determine unequivocally the genotype of every pup in seven litters. By its rapidity, its simplicity, and reliability, this method of genotype identification may be useful to many investigators.