A cross between two organisms that differ in two genes is called what?

• A. Monohybrid cross
• B. Dihybrid cross
• C. Hybrid cross
• D. Pedigree cross

Answer: (B)

When you look at how two traits are passed on at once, you’re analyzing how two gene loci segregate and combine in offspring. This is a dihybrid cross. It extends Mendel’s ideas to two genes, often revealing whether the genes assort independently (assuming they’re not linked). If both parents differ for both traits and are heterozygous at both loci, you typically see a 9:3:3:1 distribution among the offspring, reflecting all the possible allele combinations from independent assortment. A monohybrid cross, by contrast, involves just one gene and yields a 3:1 ratio, while a pedigree cross refers to tracing inheritance through family lines rather than performing a two-trait cross.