Answer to Question #107440 in Biology for Lonely person

Question

Analyze It
Tom and Alice are the parents of four children. Tom has earlobes that are not attached to the side of his head, which is a dominant trait. Alice has earlobes that are attached, which is a recessive trait. Use the two Punnett squares ("E" represents the dominant earlobe gene, and "e" represents the recessive earlobe gene) to answer the following questions.

What must be true about the earlobes of Tom's parents?

What must be true about the earlobes of Alice's parents?

Which Punnett square allows for the possibility that Tom and Alice's children have attached earlobes?

Answer 1

E*(Tom) x ee (Alice)

1)  Tom's parents: at least one of his parent must have had the dominant allele E (if Tom is heterozygous), or both of them must have possessed the dominant allele is Tom is homozygous.

2)  Alice's parents: both of her parents possessed the recessive allele e, so their possible genotypes could have been Ee or ee.

3)  The possibility of Tom and Alice's children to have attached earlobes will be only if Tom is heterozygous - Ee. So Ee x ee will result in 2 Ee and 2 ee in 1st generation. 1/2 possibility of having children with attached earlobes.