Question

Free earlobes are dominant over attached earlobes. What is the probability that a woman with attached earlobes (homozygous recessive) will have children with attached earlobes if their father has free earlobes (heterozygous)?

Answer 1

The correct answer is explained below:

Explanation:

• According to the question, free ear lobes are dominant over attached ear lobes.
• Let the allele for free ear lobes be represented by F.
• Let the allele for attached ear lobes be represented by f.
• The genotype of the homozygous recessive woman (mother) having attached ear lobes is : ff.
• The gamete produced by the woman is: f.
• The genotype of the heterozygous man (father) with free earlobes is: Ff.
• The gametes produced by the man are: F and f.
• Mating the man with the woman we get the following offspring,

                                        F                                            f

                           f           Ff                                          ff

          Phenotype      Free ear lobe                   Attached ear lobe

• The genotype and the phenotype of the probable children obtained is represented in the Punnett square above.
• The probability that the parents would produce children with attached ear lobes is = $\frac{1}{2}$ .