In a series of crosses between two true-breeding strains of peaches, the F₁ generation was uniform, producing 30-g peaches. The F₂ fruit mass ranges from 38 to 22 g at intervals of 2 g. Using these data, determine the number of polygenic loci involved in the inheritance of peach mass.

Key Concepts

Polygenic Inheritance

Polygenic inheritance refers to the genetic mechanism where multiple genes (loci) contribute to a single trait, resulting in a continuous range of phenotypes. In the case of peach mass, this means that several genes influence the weight of the fruit, leading to variations in the F₂ generation.

Quantitative Trait Loci (QTL)

Quantitative Trait Loci are specific regions of the genome that correlate with variation in a quantitative trait, such as fruit mass. By analyzing the distribution of phenotypes in the F₂ generation, researchers can estimate the number of QTLs involved in the trait's inheritance.

Phenotypic Variation and Distribution

Phenotypic variation refers to the observable differences in traits among individuals, which can be measured and analyzed. The range of peach masses from 22 g to 38 g indicates a continuous distribution, suggesting that multiple alleles contribute to the trait, which is a hallmark of polygenic inheritance.