There is a teacher from Texas that loves hairless guinea pigs. In guinea pigs, the dominant allele H codes for the trait of having hair and the allele h codes for the trait of being hairless. (Assume Mendelian inheritance). Let’s say that this teacher receives her wish of finding a hairless guinea pig at a pet store and names her Genevieve. She finds another guinea pig at a store with hair that she names Fred. While she can be certain of Genevieve’s genotype, how could she determine what genotype Fred is? She can do a test cross! A test cross involves breeding an organism with a dominant trait (like Fred) with an organism that exhibits a recessive trait (like Genevieve).

9. Genevieve has the genotype .

10. Fred’s genotype could be or .

11. If Fred was genotype and bred with Genevieve…

13. If Fred was genotype and bred with Genevieve…