Dihybrid crosses

Front

What is a dihybrid cross?

Back

A genetic cross that involves two traits, each represented by two alleles.

Front

What does the term 'allele' mean?

Back

An allele is a variant form of a gene that can produce different traits.

Front

What is the purpose of a Punnett square?

Back

To predict the genotypes and phenotypes of offspring from a genetic cross.

Front

In a dihybrid cross, how many different combinations of alleles can be produced?

Back

Four combinations of alleles can be produced from two traits.

Front

What is the phenotypic ratio expected from a dihybrid cross?

Back

The expected phenotypic ratio is 9:3:3:1.

Front

What does homozygous mean?

Back

An organism is homozygous for a trait if it has two identical alleles for that trait.

Front

What does heterozygous mean?

Back

An organism is heterozygous for a trait if it has two different alleles for that trait.

Front

What is the genotype for a plant that is homozygous dominant for both traits?

Back

AABB.

Front

What is the genotype for a plant that is heterozygous for one trait and homozygous recessive for another?

Back

AaBB.

Front

If a plant has the genotype 'Aabb', what are its phenotypes?

Back

It will express the dominant trait for the first gene and the recessive trait for the second gene.