Dominant & Recessive Traits

Introduction

Individuals receive two versions of each gene, known as alleles, from each parent. If the alleles of a gene are different, and only one allele is expressed, it is known the dominant gene. The effect of the other allele, called recessive, is masked.

Analysis

• • Open the Results of Class Phenotype Survey. and create a bar chart which shows the frequency of each phenotype. Color the dominant traits red, and the recessive traits blue.

  • Open your own copy of the survey data.

Interpretation

• • Which phenotypes are the most common in the population? Which phenotypes are the rarest?

  • Are phenotypes of dominant alleles always more common than phenotypes of recessive alleles? Explain.

  • Explain the difference between allele dominance and frequency.