Overview and Objectives - Basic Gene Inheritance

This lesson reviews the basics of gene inheritance. It compares plants that are homozygous, heterozygous, and hemizygous for an allele and how gene expression is affected by the dominance of an allele. It also explains how to use a Punnett square to predict genotypic and phenotypic ratios of offspring.

At the completion of this lesson, you should be able to:

  • Describe the difference between a plant that is hemizygous, homozygous, and heterozygous for a trait.
  • Explain how you could tell if a plant was homozygous or heterozygous and how allele dominance would affect this.
  • Compare the expression of a dominant allele with that of a recessive allele.
  • Describe a test to determine if a plant was homozygous or heterozygous for a dominant allele.
  • Demonstrate the inheritance of transgenes using Punnett squares. Predict ratios of progeny phenotype and genotype.
Peer Reviewed Web Lesson JNRLSE Approved 2003

Development of this lesson was supported in part by Cooperative State Research, Education, & Extension Service, U.S. Dept of Agriculture under Agreement Number 98-EATP-1-0403 administered by Cornell University and the American Distance Education Consortium (ADEC). Any opinions, findings, conclusions or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the view of the U.S. Department of Agriculture.