Unattached earlobes (EE or Ee)are described in the textbook as dominant over attached earlobes (ee).A couple both have unattached earlobes.Both notice that one of their parents on both sides has attached earlobes (ee).Therefore,they correctly assume that they are carriers for attached earlobes (Ee).The couple proceeds to have four children.
A)They can be certain that three will be heterozygous and one homozygous recessive.
B)If the first three are heterozygous,the fourth must be homozygous recessive.
C)The children must repeat the grandparents' genotype (Ee).
D)All children must have unattached earlobes since both parents possess the dominant gene for it.
E)Two heterozygous,one homozygous recessive,and one homozygous dominant is a likely outcome,but all heterozygous,or two,three,or all four homozygous are also possible.

Question

Quizplus · Accepted Answer

The couple, both being heterozygous (Ee), can have children with genotypes EE, Ee, or ee. The probability for each child is independent, so various combinations are possible, including all heterozygous, some homozygous dominant, or some homozygous recessive.

Unattached Earlobes (EE or Ee)are Described in the Textbook as Dominant