Chapter 28: Complex and Quantitative Traits

Exam 2 material

1. What are complex traits?  Are they influenced by the environment? Is it possible to define them numerical?

What are quantitative traits? Are they influenced by the environment? Is it possible to define them numerically?

What is continuous variation? What are meristic traits?

Define polygenic inheritance.

How do you identify single gene cross such from crosses that represent quantitative traits?

Explain the major points embodied in the multifactorial/multigene hypothesis explaining quantitative variations.

Do Mendel’s law of equal segregation and independent assortment continue to be obeyed in inheritance of quantitative traits?

Describe the details of Nilsson-Ehle experiment. What was the proportion of offspring showing the extreme phenotypes?

What is suggested about the number of genes controlling the trait in the Nilsson-Ehle experiment?

Given two sets of experimental data showing traits controlled by one or more genes, how would you predict whether there was a strong influence of the environment in determining the trait.

If a quantitative trait controlled by many different genes and also influenced by
environment was studied and plotted, what would the approximate frequency distribution of this trait appear as?

What are QTLs or quantitative trait loci? What is a general scheme for mapping
them?