One of the forms of cataract and one of the forms of deaf-dumbness are transmitted as autosomal recessive signs.

One of the forms of cataract and one of the forms of deaf-dumbness are transmitted as autosomal recessive signs. what is the probability of having children with two anomalies in a family where both parents are diheterozygous for two pairs of traits?

Let us designate the gene that causes the development of cataracts in a person as k, then the gene that determines the well-being in relation to this disease will be designated as K.

Let’s designate the gene that causes the development of deaf-dumbness as l, then the gene that causes normal hearing will be L.

Diheterozygous parents, according to the introduced designations, will have the KkLl genotypes and produce four types of spermatozoa and eggs – kl, KL, Kl, kL.

The offspring of this married couple will be represented by the following possible options:

healthy children (4 KkLl, KKLL, 2KkLL, 2KKLl) – 56.25%;

children with hereditary deaf-dumbness (2Kkll, KK ll) – 18.75%;

children with hereditary deafness and cataracts (kkll) – 6.25%;

children with cataracts (kkLL, 2kkLl) – 18.75%.

Answer: the probability of the birth in this family of children with the two anomalies under consideration is 6.25%.