In humans, there is a gene that controls formation (or lack thereof) of muscles in the tongue that allow people with those muscles to roll their tongues, while people who lack those muscles cannot role their tongues. The ability to roll one's tongue is determined by an allele that is dominant over the non-rolling version. The ability to taste certain substances is also genetically controlled. For example, there is a substance called phenylthiocarbamate (PTC for short), which some people can taste (the dominant trait), while others cannot (the recessive trait). Let R represent the tongue-rolling allele, r the non-roller allele, T represent the allele that confers the ability to taste PTC, and t represent the non-tasting allele.
What would the possible genotypic and phenotypic ratios in the children of a heterozygous tongue rolling parent that cannot taste PTC and another parent that is non-tongue roller and heterozygous for PTC tasting trait?
