LabBench Activity

Key Concepts

We say that like comes from like, but offspring do not always look exactly like their parents. In this laboratory you may breed two parent flies with red eyes and get some offspring with sepia (deep brown) eyes. How is this possible?

parent and offspring flies

In the nineteenth century Gregor Mendel discovered the principles of inheritance through a series of careful experiments with peas. We know now that physical characteristics are transmitted from generation to generation according to some general patterns. When we have sufficient information about the parents, we can predict the occurrence of traits in offspring. And by analyzing the offspring, we can discern the mode of transmission — monohybrid or dihybrid, sex linked or autosomal.

To do this laboratory, you are expected to understand basic Mendelian genetics and chi-square analysis. If any of the following concepts are unclear to you, review the genetics section in your textbook before continuing: