Humans carry two alleles for earlobe shape E for freehanging

Humans carry two alleles for earlobe shape: E for free-hanging earlobes and e for attached earlobes. Considering that free-hanging earlobes are dominant to attached earlobes, please draw a Punnett Square in the space below crossing a heterozygous individual with free-hanging earlobes with an individual with attached earlobes and include what the percentage of the offspring is homozygous dominant, homozygous recessive, heterozygous, attached earlobes and free-hanging earlobes.

Solution

Ear lobes ( E ,e ): It has illustrated that “homozygous recessive (ee) individuals possess attached ear lobes” whereas “heterozygous (Ee) or homozygous dominant (EE) individual possess “free ear lobes”. Therefore, “a child” who is born with attached ear lobes will have the following genotypes. His parents have free ear lobes means they have heterozygous (Ee) dominant individuals

E for free-hanging earlobes and e for attached earlobes.

Considering that free-hanging earlobes are dominant to attached earlobes,

A Punnett Square: Ee (heterozygous free earlobes) x    ee (homozygous recessive attached ear lobes)

e

e

E

Ee

Ee

e

ee

ee

The percentage of the offspring is homozygous dominant --> 0%

The homozygous recessive offspring (attached earlobes) --> 50%

The heterozygous and free-hanging earlobes                    ---> 50%