1. Test Crosses

2. How can you find the genotype of a dominant phenotupe?
If you have a guinea pig with a dominant phenotype, what’s the possible genotype(s) for that trait?
homozygous dominant or heterozygous
If the guinea pig has a recessive phenotype, what’s the possible genotype(s) for that trait?
homozygous recessive
How can you use what you know about dominant/recessive to find the ACTUAL genotype of that dominant phenotype?
Do a test cross!
crossing a dominant phenotype with a recessive phenotype will determine the dominant genotype

3. Test Cross
Guinea pig with folded ears (dominant phenotype) – is the guinea pig EE or Ee?
If you cross it with a straight-eared guinea pig (ee), you will see!
Example…