Question
Mr. Krabbs and his wife recently had a Lil’ Krabby, but it has not been a happy occasion for them. Mrs. Krabbs has been upset since she first saw her new baby who had short eyeballs. She claims that the hospital goofed and mixed up her baby with someone else’s baby. Mr. Krabbs is homozygous for his tall eyeballs, while his wife is heterozygous for her tall eyeballs. Some members of her family have short eyes, which is the recessive trait. Create a Punnett square using T for the dominant gene and t for the recessive one.
A. List the possible genotypes and phenotypes for their children.
B. Did the hospital make a mistake? Explain your answer.
A. List the possible genotypes and phenotypes for their children.
B. Did the hospital make a mistake? Explain your answer.
Answers
GPT-4o mini
To solve this problem, we first need to set up the genetic information given for Mr. and Mrs. Krabbs.
- Mr. Krabbs is homozygous tall eyeballs (TT).
- Mrs. Krabbs is heterozygous (Tt), with tall eyeballs as well, but she carries one allele for short eyeballs.
### A. Possible Genotypes and Phenotypes
To create the Punnett square, we'll set up Mr. Krabbs’ alleles along the top and Mrs. Krabbs’ alleles along the side:
```
T T
----------------
T | TT TT
----------------
t | Tt Tt
```
#### Genotypes:
1. TT (from T and T)
2. Tt (from T and t)
From the Punnett square, we can see the possible genotypes are:
- 50% TT
- 50% Tt
#### Phenotypes:
- Since both TT and Tt result in tall eyeballs (T is dominant), 100% of the children will exhibit the tall eyeball phenotype.
### Summary of A:
1. Possible Genotypes:
- 50% TT
- 50% Tt
2. Phenotype:
- 100% tall eyeballs
### B. Did the hospital make a mistake?
Based on the genetic information provided and the results of the Punnett square, **the hospital did not make a mistake**. Mr. Krabbs and Mrs. Krabbs can only have children with the genotypes TT or Tt, which both result in tall eyeballs due to the dominance of the tall eyeball trait (T).
Since both parents can only pass on alleles that would result in a tall eyeball phenotype, the presence of a child with short eyeballs strongly suggests that there was a mix-up, as the short eyeball trait (tt) cannot emerge from a TT and Tt pairing. Therefore, it seems likely that Mrs. Krabbs’ assertion about a mix-up is valid given the genetic outcomes.
- Mr. Krabbs is homozygous tall eyeballs (TT).
- Mrs. Krabbs is heterozygous (Tt), with tall eyeballs as well, but she carries one allele for short eyeballs.
### A. Possible Genotypes and Phenotypes
To create the Punnett square, we'll set up Mr. Krabbs’ alleles along the top and Mrs. Krabbs’ alleles along the side:
```
T T
----------------
T | TT TT
----------------
t | Tt Tt
```
#### Genotypes:
1. TT (from T and T)
2. Tt (from T and t)
From the Punnett square, we can see the possible genotypes are:
- 50% TT
- 50% Tt
#### Phenotypes:
- Since both TT and Tt result in tall eyeballs (T is dominant), 100% of the children will exhibit the tall eyeball phenotype.
### Summary of A:
1. Possible Genotypes:
- 50% TT
- 50% Tt
2. Phenotype:
- 100% tall eyeballs
### B. Did the hospital make a mistake?
Based on the genetic information provided and the results of the Punnett square, **the hospital did not make a mistake**. Mr. Krabbs and Mrs. Krabbs can only have children with the genotypes TT or Tt, which both result in tall eyeballs due to the dominance of the tall eyeball trait (T).
Since both parents can only pass on alleles that would result in a tall eyeball phenotype, the presence of a child with short eyeballs strongly suggests that there was a mix-up, as the short eyeball trait (tt) cannot emerge from a TT and Tt pairing. Therefore, it seems likely that Mrs. Krabbs’ assertion about a mix-up is valid given the genetic outcomes.