ability to roll one's tongue?

Question

the ability to roll one's tongue is a dominant trait. Jane and Allen are both heterozygous for the trait. What are the chances that their first child will be a boy who can roll his tongue?


4/4

3/4

3/8

1/8

Answer 1

Parents are heterozygous: Rr x Rr.
3/4 chance of having an R and being a tongue roller.

Answer 2

OK this is a bit of a trick question, the answer is 3/8. You're actually being asked about two possibilities. The first is the chance of a boy and the next is the chance of a tongue roller. The chance of a boy is 1/2 and the chance of a tongue roller is 3/4, multiply these two numbers and you get 3/8.

Answer 3

R=dominat trait, r=recessive trait. Two heterozygous people would have a probablity of 3/4 of their child being able to roll their tounge.

Answer 4

Various tongue rolling abilities are dependent on dominant or recessive genes. Tongue rolling is a domimant gene being expressed, while tongue folding is a recessive gene being expressed, for example. If you inherit the genes trait you inherit the ability.