Thursday, May 12, 2011

The Genes Will Tell: Take it to the Lab!

The study of genetics and heredity has been a part of science curriculum for quite a while now. Biology teachers can use the experiments and discoveries of Gregor Mendel along with Darwin’s explanation of natural selection to teach students the inner workings of genetics and heredity. Although I find the subject fascinating, students may tire of doing endless homozygous and heterozygous crosses on worksheets. Some of these worksheets and “boring” lessons can be replaced by some of the unique activities featured in Joann’s Picks and on our Facebook and Twitter pages this week. For example, instead of figuring out what the offspring of two pea plants will look like, students can learn the same concepts by working out crosses between characters in the Harry Potter books! If students aren’t excited about figuring out the phenotypes and genotypes of real animals, maybe they would learn better with Dragon Genetics. Joann will be featuring many more fun resources like this throughout the week.

With today’s technology and a much more detailed understanding of DNA and the human genome, students can go beyond punnet squares and Mendelian genetics to actually work with DNA. This is possible, even for classes with limited lab supplies. Movies and television shows are full of crimes and medical mysteries being solved with DNA analysis. What if our students had a chance work with DNA and learn how to use it to solve a mystery? Here is a sampling of resources that can help you do just that. Most of these activities were written for high school students, but some middle school clsasses could use them also.

Students can extract DNA from living organisms found in their own kitchens (and I’m not talking about that moldy bread in the pantry!). There are some well-written and easy to follow lab activities on the Gateway to help your students extract DNA from different fruits (Fruitful DNA Extraction) or an onion (Isolation of DNA from an Onion). This is a neat opportunity to see and even feel a real sample of DNA.

The shows on TV aren’t pinning crimes on produce, though, and we don’t have a crime scene with DNA evidence for our students to collect. The next best thing we can do on a low budget is a computer simulation that allows students to conduct a virtual experiment. PBS has a nice simulation to supplement a NOVA program. This simulation, Create a DNA Fingerprint, requires Shockwave, which is a free download from Adobe. This is an online crime-solving activity where students get first hand experience with cutting edge lab work without the expense of all the lab equipment. By the end of the experiment, the students have created a DNA fingerprint to compare to all the suspects. I recommend trying the lab ahead of time. I got the right culprit the first time!

One of the techniques in the above simulation is called electrophoresis, an important step in the process of creating a DNA fingerprint. If you are lucky enough to have a very well-stocked biology lab, you could do activities like Extracting and Analyzing Our Own DNA from the University of Arizona. These activities allow high school students to extract and analyze their own DNA with agarose gel electrophoresis, along with other labs. The activities culminate with a case study of Harris hawks in the southwest United States. If you want to do a simple activity with electrophoresis using household supplies, try building an electrophoresis chamber from The Gene Hunters. Students will have fun doing some of these crime-solving techniques they see on TV.

A while ago, we featured resources about the Russian Revolution in our columns. I found a neat connection to this topic as I was searching the Gateway for genetics activities. Recovering the Romanovs is an introduction to a genetics unit using the Romanov family. Students study the way scientists can use the link between DNA and hemophilia to separate the real Romanovs from the imposters. If your students studied the Russian Revolution, this would be a really neat cross-curricular connection.

~Peggy's Corner - 5/6/2011~

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