What is a cross that involves two pairs of alleles from different parents called?

A cross that involves two pairs of alleles from different parents is referred to as a dihybrid cross. This type of genetic cross examines the inheritance of two distinct traits, each controlled by different alleles. For instance, when studying two traits simultaneously, such as seed color (yellow or green) and seed shape (round or wrinkled) in pea plants, a dihybrid cross tracks how these traits segregate and assort during the formation of gametes and subsequent offspring.

In a dihybrid cross, the parent organisms will each contribute two alleles for each trait, allowing the offspring to exhibit a combination of the traits that result from these inherited alleles. The inheritance patterns and ratios observed from the offspring help demonstrate Mendel's Law of Independent Assortment, which states that different pairs of alleles segregate independently during gamete formation.

Understanding the concept of a dihybrid cross is important for studying genetic variations and predicting phenotypic outcomes in offspring, making it a foundational element of classical genetics.