Genetics Quiz

Examine the Punnett square below. Which of the following is not correct outcome of crossing over?

In humans, being a tongue roller (R) is dominant over non-roller (r). A man who is a non-roller marries a woman who is heterozygous for tongue rolling. What is the genotypic ratio of the probable offspring?

• 2:1

• 2:2

• 3:1

• 1:3

Problem: Hornless (H) in cattle is dominant over horned (h). A homozygous hornless bull is mated with a homozygous horned cow. What is the genotype of the parents?

• Hh-hh

• HH-hh

• Hh- Hh

• Hh-HH

What is the genotypic ratio of the offspring?

• 2 HH: 2 Hh

• 2 hh: 2HH

• 4 Hh

• 4 HH

What is the phenotypic ratio of the offspring?

• 2 hornless: 2 horned

• 3 hornless: 1 horned

• 4 horned

• 4 hornless