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

Answer 1

In this scenario, where tongue-curling (T) is a dominant trait and non-curling (t) is a recessive trait, we can use a Punnett square to determine the possible genotypes and phenotypes of the children from a Tt (tongue-curler) father and a Tt (tongue-curler) mother.

The parental genotypes are:
- Father: Tt
- Mother: Tt

We can set up the Punnett square as follows:

```
T t
----------------
T | TT | Tt |
----------------
t | Tt | tt |
----------------
```

From the Punnett square, the possible genotypes for their children are:
- **TT** (homozygous dominant, tongue-curler)
- **Tt** (heterozygous, tongue-curler)
- **tt** (homozygous recessive, non-tongue-curler)

Counting the combinations:
- **TT**: 1
- **Tt**: 2
- **tt**: 1

Now, calculating the percent chance for each genotype:
- **TT**: 1 out of 4 = 25%
- **Tt**: 2 out of 4 = 50%
- **tt**: 1 out of 4 = 25%

Since both TT and Tt result in a tongue-curling phenotype:
- Phenotype for TT: Curl
- Phenotype for Tt: Curl
- Phenotype for tt: No Curl

Thus, the phenotype percentages would be:
- Curl: 3 out of 4 = 75%
- No Curl: 1 out of 4 = 25%

In summary:

- **Genotype**:
- TT: 25%
- Tt: 50%
- tt: 25%

- **Phenotype**:
- Curl: 75%
- No Curl: 25%

So the final answer is:
- **TT**: 25%
- **Tt**: 50%
- **tt**: 25%

Additionally, for phenotypes:
- **Curl**: 75%
- **No Curl**: 25%