Question

in humans tongue rolling is a dominant trait those with the recessive condition cannot roll their tongues. grant can roll his tongue, but his mother could not. what is grant's genotype?

Answer 1

Grant’s genotype would likely be Aa (a heterozygote for the tongue rolling alleles). Grant’s mom cannot roll her tongue, meaning she is “aa”. Grant can roll his tongue, meaning he has at least one “A”. Because Grant’s mom is “aa”, she can only pass down a “a” allele. If Grant needs to have a “a” allele from his mom, AND an “A” allele to be able to roll his tongue, he would likely be a heterozygote, or Aa.