What is the term for crossing two variants of the same characteristic?

• A. Multiple-factor cross
• B. Single-factor cross
• C. Double-factor cross
• D. True-breeding cross

Answer: (B)

The term for crossing two variants of the same characteristic is referred to as a single-factor cross. This type of cross, also known as a monohybrid cross, involves examining one characteristic or trait at a time, allowing for the observation of how different alleles for that single trait segregate when gametes combine.

In a single-factor cross, the focus is on tracking the dominance and recessiveness of alleles involved in that one specific trait. For example, when crossing pea plants with different flower colors, one can observe the inheritance patterns of the allele for purple flowers versus the allele for white flowers. This simplification enables a clearer understanding of basic inheritance principles, such as Mendel’s laws of segregation.

In contrast, a multiple-factor cross examines two or more traits simultaneously, which complicates the genetic analysis. A double-factor cross specifically looks at two traits and their inheritance patterns, while a true-breeding cross typically involves homozygous individuals to ensure that offspring exhibit predictable traits, often involving one characteristic but focusing on producing pure lines. Thus, the term that specifically describes the crossing of two variants of one characteristic is indeed a single-factor cross.