Table of Contents
Dihybrid Cross (The Two Trait Cross)
Mendel continued his experimentation where he looked at two traits. These two trait crosses are called dihybrid crosses. While the monohybrid cross would yield 3:1 ratios of the phenotypes, the dihybrid crosses would yield 9:3:3:1 ratios of all the combinations of each phenotype.
Mendel’s Rule of Independent Assortment
The dihybrid cross revealed another law of inheritance to Mendel. By observing the 9:3:3:1 ratio, Mendel concluded that traits were not tied to each other. That is to say, if a pea pod was yellow, it could still be either smooth or wrinkled in texture. This lack of linkage between genes yielding different characteristics was dubbed the Law of Independent Assortment. Genes for different traits can segregate independently during the formation of gametes.
Review of Mendelian Genetics
Additional Reading and Resources
- Mendelian Inheritance
- Independent Assortment
- Genetics and Statistical Analysis
- Genetic Linkage
- DNA as the Genetic Material
- What Is a Gene?
