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Genotype Versus Phenotype

by Greg Crowther


The distinction between genotype and phenotype can be confusing to introductory biology students. This song was written as a study aid for these students -- specifically, the students in Biological Frameworks for Engineers at the University of Washington (ChemE 355/599 and EE 400/546). The chorus was inspired by Kool and the Gang's "Tonight."


I'll start this by noting
That genes encode proteins,
Which dictate cell function and form.
So if a gene mutates,
The cell may gain new traits
Far better or worse than the norm.

Genotype -- ooh...
The alleles you possess;
Nothing more, nothing less --
Versus phenotype -- ooh...
Your appearance and health
And reproductive success.

In some situations,
There is a mutation,
Yet phenotype stays just the same.
So guessing the genotype
Just from the phenotype
Can be a difficult game.


Other Files

sheet music (with melody play-back)

Lesson Plan

Songs like this one can be used during class meetings and/or in homework assignments. Either way, the song will be most impactful if students DO something with it, as opposed to just listening.

An initial, simple follow-up activity could be to answer the study questions below. A more extensive interaction with the song might entail (A) learning to sing it, using an audio file and/or sheet music as a guide, and/or (B) designing kinesthetic movements ("dance moves") to embody it. The latter activity could begin with students identifying the most important or most challenging content of the song, and deciding how to illustrate that particular content.

Study Questions

(1) Why might a genotype change (mutate)?

(2) What general kinds of changes in genotype are more likely and less likely to cause changes in phenotype?

(Answers may be found on the answers page.)