Question

In humans, to fold the tongue is a dominant trait (L), and the straight tongue is the recessive trait. What are the probabilities that the offspring can fold the tongue?

Answer 1

The given question is incomplete as the genotype of the parents is not given, so the answer is providing in the followings case:

1. dominant parent and recessive parent

2. heterozygous parents

Answer:

1. dominant parent and recessive parent:

dominant parents can be represented by LL and recessive parent is represented by ll, so the gametes would be L, L and l, l.

so,

 L    L

l  Ll   Ll

l  Ll   Ll

so there are all offspring in heterozygous condition as we known one or two dominant allele masks the recessive allele for the trait so 100% offspring can fold their tongue.

2. heterozygous parents

In this case, parents have Ll genotype and gametes would be L and l for each parent so,

    L    l

L   LL  Ll

l    Ll    ll

In this case, one is pure dominant and two heterozygous whereas only one is recessive so, the phenotype of offspring that cant fol the tongue would be:

3/4 = 75%