Dihybrid Crosses

Front

What is a dihybrid cross?

Back

A dihybrid cross is a genetic cross that examines the inheritance of two different traits, each controlled by different genes.

Front

What is the genotype of an organism?

Back

The genotype is the genetic makeup of an organism, represented by the alleles it possesses.

Front

What is the phenotype of an organism?

Back

The phenotype is the observable physical or biochemical characteristics of an organism, determined by its genotype.

Front

What does homozygous mean?

Back

Homozygous refers to having two identical alleles for a particular gene (e.g., RR or rr).

Front

What does heterozygous mean?

Back

Heterozygous refers to having two different alleles for a particular gene (e.g., Rr).

Front

In a dihybrid cross, what is the phenotypic ratio of the offspring?

Back

The phenotypic ratio of a typical dihybrid cross is 9:3:3:1.

Front

What is the purpose of a Punnett square?

Back

A Punnett square is used to predict the genotypes and phenotypes of offspring from a genetic cross.

Front

What is the significance of dominant and recessive alleles?

Back

Dominant alleles mask the effect of recessive alleles in determining the phenotype.

Front

If a plant has the genotype RrYy, what gametes can it produce?

Back

The plant can produce four types of gametes: RY, Ry, rY, and ry.

Front

What is the expected genotype ratio from a dihybrid cross of two heterozygous parents (RrYy x RrYy)?

Back

The expected genotype ratio is 1 RRYY : 2 RRYy : 2 RrYY : 4 RrYy : 1 rrYY : 2 rrYy : 1 rryy.