Question

In humans, free-ear lobes are dominant to attached lobes. Two parents that are both heterozygous free are excepting a child. Show the probabilities for this cross

P:
Genotypic ratio:
Phenotypic ratio:

Answer 1

Answer: Phenotypic Ratio is 3:1 and genotypic ratio is 1:2:1

Explanation:

Since free lobes are dominant, let's represent that as F, and since attached earlobes are recessive, let's demonstrate that as f.

So, if the parents are heterozygous (have both alleles F & f), then the cross will be Ff x Ff. When you do the punnett square for that the four possible genotypes will be FF, Ff, Ff, and ff.

Phenotype: the physical appearance of an organism.

Genotype: the genetic makeup of am organism (results of punnet square)

So, since dominant always presides over recessive and three of our punnet square have capital F as the first letter (dominant), then those three will show the dominant trait, which is free ear lobes. And the one individual with ff will show the recessive trait (attached ear lobes). So the phenotype ratio is 3:1.