Genetics portfolio worksheet Name:______

1. A couple have children of blood groups A and AB. This couple cannot have children of blood groups O or B.

a) What are the possible genotypes of the couple?

b) Write out the possible crosses involved.

2. Predict the phenotypes and genotypes of the offspring from a dihybrid cross between a pure-breeding pea plant with yellow, round seeds and a pure-breeding pea plant with green, wrinkled seeds. In pea plants, yellow is dominant over green, and round is dominant over wrinkled.

3. The pedigree above represents the inheritance of colourblindness (an x-linked condition) within a given family. Who are the confirmed carriers of colourblindness in this family? Fill in the genotypes in the pedigree to show how you arrived at your answer.

4. Explain why lethal recessive genes can be maintained in a population and why they are much more abundant than lethal dominant genes.

5. In a certain species of plants, scented and odourless flowers occur, together with hairy and smooth stems. A scented, smooth-stemmed plant was crossed with a fully homozygous odourless plant with hairy stems. Indicate the possible genotypes and phenotypes of the parents and offspring that would produce four kinds of phenotypes among the offspring, in equal numbers (1:1:1:1). Assume scented and smooth are dominant.

6. The pedigree below represents a family tree showing hemophilia.

a) State the genotype for individuals 1 and 2 in generation

b) Explain your rationale.

7. B is the allele for the dominant, black hair characteristic; b is the allele for the recessive, light hair characteristic. T is the allele for the dominant, tongue-rolling characteristic; t is the allele for the recessive, non-tongue rolling characteristic. A father is heterozygous for black hair and heterozygous for tongue-rolling. The mother is light-haired and heterozygous for tongue-rolling.

a) Construct a punnet square showing all the possible genotypes and state the phenotypes of the offspring.

b) What is the probability of having a child with light hair who is a tongue-roller?