Brown eye color dominates over blue, and rounded eyebrows are arched. A brown-eyed man with arched
Brown eye color dominates over blue, and rounded eyebrows are arched. A brown-eyed man with arched eyebrows married a blue-eyed woman with rounded eyebrows, whose father had arched eyebrows. What kind of children will this family have?
Let’s designate the gene that causes the development of brown eyes as H, then the gene that causes the development of blue eyes will be h.
Let’s designate the gene that causes the development of rounded eyebrows as K, then the gene that causes the development of arched eyebrows will be k.
The woman’s father had arched eyebrows, the development of which was determined by the homozygous kk genotype. He could pass on to his daughter only the recessive gene for arched eyebrows k.
Consequently, a woman with rounded eyebrows is heterozygous for this trait.
It has the hhKk genotype and produces two types of egg cells – hK, hk.
A brown-eyed man with arched eyebrows can be either homo- or heterozygous for the eye color gene. Let’s consider both options.
Let the male be HHkk, he will produce Hk sperm. In a marriage with the woman described above, the offspring will be represented by the options:
brown-eyed children with rounded eyebrows (HhKk) – 50%;
brown-eyed children with arched eyebrows (Hhkk) – 50%.
Let the man be Hhkk, he will produce two types of sperm – Hk, hk. Offspring married to the woman described above will be represented by the following options:
brown-eyed children with rounded eyebrows (HhKk) – 25%;
brown-eyed children with arched eyebrows (Hhkk) – 25%;
blue-eyed children with rounded eyebrows (hhKk) – 25%;
blue-eyed children with arched eyebrows (hhkk) – 25%.