Download PTC Genes and Bitter Taste

Name: _________________________________________
Period: ________
PTC: Genes and Bitter Taste
Directions:
 Go to the following website:
http://learn.genetics.utah.edu/content/inheritance/ptc/
 Read the information and listen to the clips provided on PTC: Genes and Bitter Taste.
 Answer the website questions below.
 Complete the pedigree on the back and answer the questions that go along with it.
Website Questions:
1. Who was the scientist that discovered the PTC taste variation among people?
2. What percentage of the population are tasters? Non-tasters?
3. What is the PTC gene and when was it discovered?
4. What does PTC stand for?
5. What is the evolutionary purpose for the ability to taste bitterness?
6. What is the pattern of inheritance shown by PTC tasting?
7. Is the ability to taste PTC solely based on someone’s genotype? Why or why not?
Determine the genotype(s) for the family members in the pedigree below using what you learned
about the ability to taste PTC. Use T and/or t in your genotypes.
Pedigree Questions:
1. Complete a Punnett square for the couple labeled 3 and 4. Determine the probabilities for each
possible genotype for their offspring.
2. Complete a Punnett square for the couple labeled 6 and 7. Determine the probabilities for each
possible genotype for their offspring.
3. Assume the female labeled #12 marries a man and has one child. That child is a non-taster.
What is #12’s genotype? What is her husband’s genotype? What is their child’s genotype?