The gene for brown eyes dominates over the gene for blue eyes, and deafness is a recessive trait

| February 8, 2021 | education

The gene for brown eyes dominates over the gene for blue eyes, and deafness is a recessive trait, and both pairs of genes are located on different chromosomes. Determine the probability of birth of deaf children in the family if both parents are healthy, brown-eyed and heterozygous for both pairs of genes.

Let the gene for brown eyes in humans be K, then the gene for blue eyes is k.

Let the gene for deafness be l, then the gene for normal hearing is L.

Diheterozygous, according to the condition of the problem, the parents have brown eyes and normal hearing – KkLl. They are capable of producing four types of spermatozoa and eggs – kl, KL, Kl, kL.

The offspring of the specified married couple will include the following possible options:

children children with normal hearing and brown eyes (4 KkLl, KKLL, 2KkLL, 2KKLl) – 56, 25%;

children with deafness and brown eyes (2Kkll, KK ll) – 18.75%;

children with deafness and blue eyes (kkll) – 6.25%;

children with normal hearing and blue eyes (kkLL, 2kkLl) – 18.75%.

Answer: The probability of a given married couple having deaf children is 25%.



One of the components of a person's success in our time is receiving modern high-quality education, mastering the knowledge, skills and abilities necessary for life in society. A person today needs to study almost all his life, mastering everything new and new, acquiring the necessary professional qualities.