1. Genetic Factors Activity
Which is longer, your index finger or your ring finger?

2. Genetic Factors Activity
Males:
Dominant: Long ring finger
Recessive: Long index finger
Females:
Dominant: Long index finger
Recessive: Long ring finger

3. Genetic Factors Activity
Phenylthiocarbamide (PTC) tasting
There is a single gene which codes for a protein found in our tongues. PTC will bind with the protein if present and a person will taste it
Are you a taster or non-taster?
About 70% of the US population tastes the bitter chemical
About 1/3 of the tasters will be “super tasters” – because they are homozygous for the dominant allele the taste is extra bitter
The other 30% tastes nothing

4. Genetic Factors Activity
Interesting PTC Facts:
Nearly 100% of Native Americans are tasters
People who can taste PTC are more likely to be non-smokers and not in the habit of drinking coffee or tea
People who are super tasters are more likely to find green vegetables bitter
Women, Asians, and African-Americans are all more likely to be super tasters

5. Questions
1) A man with red hair (recessive) marries a woman with black hair (dominant) whose mother had red hair. What are the chances their first child would have red hair? Black hair?
2) A man and a woman both have blue eyes, but their first child has brown eyes. What are the chances that their second child will also have brown eyes?