Dihybrid

Definition

A dihybrid is an organism that is heterozygous for two different traits. It carries two different alleles at two loci of interest and can produce offspring with various combinations of these traits.

5 Must Know Facts For Your Next Test

1. A dihybrid cross involves two pairs of contrasting traits.
2. The phenotypic ratio expected in the F2 generation of a dihybrid cross is typically 9:3:3:1.
3. Dihybrid crosses illustrate the principle of independent assortment, which states that alleles for different traits segregate independently during gamete formation.
4. Gregor Mendel used dihybrid crosses to formulate his second law of inheritance, also known as the Law of Independent Assortment.
5. In a Punnett square for a dihybrid cross, there are 16 possible genotype combinations.

Review Questions

• What is the expected phenotypic ratio in the F2 generation resulting from a dihybrid cross?
• How does a dihybrid cross demonstrate the Law of Independent Assortment?
• Who first utilized dihybrid crosses to study patterns of inheritance?

Related terms

Monohybrid: An organism that is heterozygous for one specific trait.

Independent Assortment: The principle stating that genes for different traits can segregate independently during the formation of gametes.

Punnett Square: A grid used to predict the genotypes and phenotypes of offspring from genetic crosses.