Introduction

Aside from Mendel’s work, researchers have been able to examine other model organisms to identify additional patterns of inheritance. One such model which demonstrates the concept of Incomplete Dominance is the snapdragon plant. Let’s see how flower color is inherited in the snapdragon…

The following video gives explains the exception to Mendel’s Laws regarding human sex chromosomes.

Summary

• Incomplete dominance occurs when both traits are expressed equally and neither parental trait is dominant or recessive to one another.
• Codominance occurs when the phenotype of a heterozygote is determined equally be each allele.
• Polygenic traits are determined by the interaction of two or more genes.
• In polygenic inheritance, the range of phenotypes is usually a continuous scale (not distinct groups).
• Environment Conditions (both internal and external) can influence the appearance of many, if not most, traits.

Sources:

“Sex-Linked Traits.” Kahn Academy. Retrieved from: https://youtu.be/-ROhfKyxgCo Licensed under: Standard YouTube License