Understanding Tongue Rolling Gene Expression Through Mendelian Genetics

What are the possible genotypes and corresponding phenotypes for tongue rolling ability based on Mendelian genetics?

Answer:

The three possible genotypes for tongue rolling are RR and Rr, both resulting in the ability to roll the tongue, and rr, resulting in the inability to roll the tongue. Options A and D are correct, while option C would be correct if it stated 'Unable to roll tongue' instead.

The ability to roll your tongue in humans is a classic example used to explain simple Mendelian genetics, where the dominant allele (R) results in the ability to roll the tongue and the recessive allele (r) results in the inability to roll the tongue. The three possible genotypes and their corresponding phenotypes are:

Genotype: RR, Phenotype: Able to roll tongue

Genotype: Rr, Phenotype: Able to roll tongue

Genotype: rr, Phenotype: Unable to roll tongue

Therefore, the correct combinations from the options given are A, D, and C (if corrected to 'Unable to roll tongue'). Option B is incorrect because having one R allele (Rr) would still result in the ability to roll the tongue due to the dominance of the R allele. Option E is incorrect because having two dominant alleles (RR) would definitely result in the ability to roll the tongue.