John can roll his tongue and is heterozygous for this dominant trait (rr). john’s second toe is shorter than his first. his wife rita cannot roll her tongue and has a longer second toe. rita is heterozygous for this dominant trait (tt). use a punnett square to predict the possible genotype(s) and phenotype(s) of their first child?

       rT       rt

Rt    RrTt     Rrtt

rt     rrtt        rrtt

25% chances for the genotype to be heterozygous roll tongue and heterozygous longer second toe.

25% chances for the genotype to be heterozygous roll tongue and homozygous short toe.

50% chances for the genotype to be  homozygous recessive no roll tongue and homozygous recessive short toe.

Phenotypes would be 25% tongue roll with longer toe. 25% tongue roll with shorter toe. 50% no tongue roll,shorter toe.

"1. it should be, it has been for about 20 years, and it's really not much different in the end than breeding animals to have particular traits. there are always concerns about genetically engineered animals/plants affecting the environment in unexpected negative ways, but i can't think of an example where the fears didn't turn out to be baseless.  

first, as you point out, it would be a great advance in pharmacology, to be able to tailor drugs and their doses to me. the pros involve better medical treatment. the cons involve privacy issues like insurance companies denying coverage to people with genetic risk factors. looking at dna markers wouldn't affect the frequency of genetic diseases, but it would allow detection of them earlier. and ok, actually i suppose that if people used this information to avoid having children with genetic diseases, some might decrease in frequency."