Tongue rolling is a dominant trait, following simple dominance. Mom can't roll her tongue but dad can. By looking at this pedigree, what can you determine about the family genotypes?

The correct genotype would be-

mom: homozygous recessive, father: heterozygous or homozygous dominant, and son : 50% (if father heterozygous dominant) to 100% (if father is homozygous dominant) chances of being hetrozygous dominant.

Explanation:

Listing the genes in the way that they indicates the real combination of alleles is the genotype of individual.

Ability to roll your tongue is a dominant character which has a dominant and a recessive gene. Assume that the dominant allele 'R' is for the ability to rolling tongue and the recessive allele 'r' for unable to rolling our tongue. As we know mother can not roll her toungue she must have homozygous recessive alleles that means she has two copy of recessive allele. The father could posess any combination of these alleles: RR (homozygous dominant), or Rr (heterozygous dominant).

Thus, the correct genotype would be

mom: homozygous recessive, father: heterozygous or homozygous dominant, and son : 50% (if father heterozygous dominant) to 100% (if father is homozygous dominant) chances of being hetrozygous dominant.