Question

Mr. And mrs. John have six children. Three of them have attached earlobes (recessive) like their father, and the other three have free earlobes like their mother. What are the genotypes of mr. And mrs. Jones and of their numerous offspring

Answer 1

Offspring genotype:

ee

ee

ee

Ee

Ee

Ee

Genotype of the parents:

Ee -mother and ee-father

Where E refers to allele for free earlobe and e refers to e refers to allele for attached earlobe.

Answer 2

The genotypes of the three children are ee (attached earlobes) and Ee (free earlobes).

• The attached earlobes are recessive and require the presence of two recessive alleles (homozygous, ee).
• Free earlobes are dominant and show their presence in homozygous (EE) or heterozygous conditions (Ee).
• Mr. John has attached earlobes and has the genotype- ee
• Mrs. John has free earlobes and has the genotype- Ee.
• Only when the child receives recessive allele from both the parents can he/she/they have attached earlobes. This is why Mrs. John cannot be homozygous dominant (EE).
• The genotypes of three children with attached earlobes are ee.
• The genotypes of three children with free earlobes are Ee.