Question

Can YOU curl your tongue up on the sides? We are pretending that tongue-curling in humans is a dominant genetic trait. Suppose a man who is Tt for tongue-curling marries a woman who is also Tt for this trait. What are the possible genotypes and phenotypes of their children, and the percent chance for each? Genotype Phenotype (curl or no curl) Percent Chance (number only) TT Tt tt Word Bank:

Answer 1

To determine the possible genotypes and phenotypes of the children from a cross between two individuals who are both Tt for tongue-curling (where T is for curling (dominant) and t is for not curling (recessive)), we can use a Punnett square.

1. **Parental Genotypes:**
- Father: Tt
- Mother: Tt

2. **Punnett Square:**
```
T | t
---------------
T | TT | Tt
---------------
t | Tt | tt
```

3. **Possible Genotypes of Children:**
- TT (homozygous dominant)
- Tt (heterozygous)
- tt (homozygous recessive)

4. **Phenotypes:**
- TT and Tt both will exhibit the curling trait (curl).
- tt will not exhibit the curling trait (no curl).

5. **Percent Chance:**
- **TT:** 1 out of 4 (25%)
- **Tt:** 2 out of 4 (50%)
- **tt:** 1 out of 4 (25%)

6. **Summary:**
- Genotype: TT - Phenotype: Curl - Percent Chance: 25
- Genotype: Tt - Phenotype: Curl - Percent Chance: 50
- Genotype: tt - Phenotype: No Curl - Percent Chance: 25

**Word Bank:**
- TT: Curl (25)
- Tt: Curl (50)
- tt: No Curl (25)