Which term describes a mating between two individuals that are heterozygous for two traits?

• A. Dihybrid cross
• B. Monohybrid cross
• C. Backcross
• D. Test cross

Answer: (A)

Verified step by step guidance

1. Step 1: Understand the meaning of 'heterozygous for two traits.' This means each individual has two different alleles for each of the two traits, for example, genotype AaBb where 'A' and 'a' are alleles for the first trait and 'B' and 'b' are alleles for the second trait.
2. Step 2: Recognize that a cross involving two individuals both heterozygous for two traits (AaBb x AaBb) is called a dihybrid cross because it examines the inheritance of two traits simultaneously.
3. Step 3: Differentiate this from a monohybrid cross, which involves heterozygosity for only one trait (e.g., Aa x Aa), focusing on a single gene.
4. Step 4: Understand that a backcross involves crossing an offspring with one of its parents or an individual genetically similar to the parent, often to study inheritance patterns or confirm genotypes.
5. Step 5: Know that a test cross involves crossing an individual with a homozygous recessive individual to determine the unknown genotype of the first individual.