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Genetics in the Laboratory

Do you want to do a great genetics lab with your students, but don't have time for fruit flies?

Having enough "time" is an issue for me every single year!  I finally had to come to the realization that my fruit fly genetics lab would have to go.  It is such a great lab, but just too time consuming.

Now we grow corn!  It only takes a few minutes to plant and you are practically done!  I do have my students water their corn every few days, and in about 2 weeks we are ready to do the lab.

In corn, green stem (due to chlorophyll production) is dominant over albino stem.  I order seeds that are the F-2 offspring of heterozygous parents.  The expected ratio when the seeds grow is, of course, 3/4 green stem and 1/4 albino stem.  Students then compare the expected ratios to the actual number of each type of offspring observed.

For an added component to the lab, have the students consider the effect of the environment on the expression of the gene. When the seeds are first planted, I have half the class place their trays on a table in front of a window.  The other half of the class place their trays in a cabinet in complete darkness. When the seeds finally sprout and grow, we compare the number of albinos grown in the dark to the number of albinos grown in the light.

For those plants grown in the light, the results are fairly close to the expected 3:1 ratio.  But, the seeds grown in the dark are a different story.  100% of the seeds grown in the dark turn out to be albino.

After this first observation, all trays are left in the light for 48 hours, and a second observation is made two days later.  Miraculously : )  about 3/4's of the albinos from the dark trays have now turned green.

Students quickly determine that the environment plays a very important role in gene expression.

If you choose, you can order seeds showing two traits as seen in the photo to the left.  When these seeds were grown, students could determine the expected and actual numbers of green and albino stems as well as the number of tall and dwarf plants.

You can view this lab in my TpT store by clicking this link:

Lab: The Effect of the Environment on Gene Expression

Or, you might want to try this as a "Virtual Lab" for distance learning and 1:1 classrooms.  You can check out the "Virtual Lab Version" by clicking this link.

1 comment:

  1. This is cool. Do you ever raise the corn and cross it yourself? I know it would go through a summer - just wondering.