Dihybrid Crosses

Front

What is a dihybrid cross?

Back

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

Front

What does homozygous dominant mean?

Back

An organism with two identical dominant alleles for a trait (e.g., AA).

Front

What is a phenotype?

Back

The physical trait that is expressed in an organism.

Front

What is a genotype?

Back

The genetic makeup of an organism, represented by alleles (e.g., AA, Aa, aa).

Front

What does it mean if an organism is homozygous recessive?

Back

An organism with two identical recessive alleles for a trait (e.g., aa).

Front

In a dihybrid cross, how many traits are being studied?

Back

Two traits are crossed.

Front

What is the purpose of a Punnett square?

Back

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

Front

What are alleles?

Back

Different forms of a gene that determine specific traits.

Front

What is the ratio of phenotypes expected in a typical dihybrid cross?

Back

9:3:3:1 ratio of phenotypes.

Front

What does it mean for a trait to be dominant?

Back

A dominant trait is expressed in the phenotype even if only one dominant allele is present.