Disease diabetes mellitus is a recessive trait d. what is the probability of having sick children in a marriage between

Disease diabetes mellitus is a recessive trait d. what is the probability of having sick children in a marriage between a carrier of the mother’s recessive gene and a healthy homozygous father (complete dominance).

Since there are two DNA strands, there are also two variants (alleles) of the gene. In the case of a carrier mother, it turns out that she is healthy, but in her genome there is one copy of the gene that causes the disease, and the second copy is healthy. The mother is healthy because the “healthy” copy of the gene is dominant and suppresses the effect of the recessive one. Father is homozygous and healthy (there are two identical copies of the “healthy” gene)

We will conventionally designate this gene by the letter D

P: Dd (mother) x DD (father)

We get the following options: DD, DD, Dd, Dd.

It can be seen that in 50% of cases homozygous healthy children will appear and in 50% heterozygous healthy children. Thus, the probability of having sick children is 0%.