Answer:
Genotypic ratio = 1:2:1
Phenotypic ratio = 3 tongue rollers : 1 non-tongue roller
Explanation:
This question involves a gene coding for the ability to roll the tongue or not in humans. The allele for tongue rolling (R) is dominant over the allele for non-tongue rolling (r).
According to this question, two individuals that are heterozygous for tongue rolling mate i.e. Rr × Rr. The proportion of offsprings that will be likely produced from this cross will be: RR, Rr, Rr, and rr.
- Offsprings with RR, Rr, Rr are tongue rollers
- Offsprings with 'rr' are non-tongue rollers.
Hence, the predicted genotypic and phenotypic ratio are as follows:
Genotypic ratio = 1 RR :2Rr :1rr
Phenotypic ratio = 3 tongue rollers : 1 non-tongue roller
