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?
In this scenario, the man is heterozygous (Tt) for the tongue-curling trait, and the woman is also heterozygous (Tt). To determine the possible genotypes and phenotypes of their children, we need to consider the different combinations of alleles that can be inherited from each parent.
Possible genotypes of offspring:
- 25% chance of the child being homozygous dominant (TT)
- 50% chance of the child being heterozygous (Tt)
- 25% chance of the child being homozygous recessive (tt)
Possible phenotypes of offspring:
- If the child has a genotype of TT or Tt, they will exhibit the tongue-curling phenotype.
- If the child has a genotype of tt, they will not exhibit the tongue-curling phenotype.
Thus, the percent chances for each genotype and phenotype are as follows:
Genotypes:
- 25% chance of TT genotype
- 50% chance of Tt genotype
- 25% chance of tt genotype
Phenotypes:
- 75% chance of exhibiting the tongue-curling phenotype (TT or Tt genotypes)
- 25% chance of not exhibiting the tongue-curling phenotype (tt genotype)