From DNA to Organism: A Study in DNA Function for the High School Biology Classroom

Module 1: Phenotype

Lab Letter

Dear Biology Students,

           My name is Dr. Berkowitz and I am a researcher working on plant genetics at a local university. I am having a problem with my research and I need your help. I spoke with your teacher earlier in the year and was told that you were good scientists and might be able to help with my problem.

           I am currently studying a plant called Arabidopsis. Arabidopsis is the white rat of plant research. It is commonly used because of its small size and quick generation time.   It is also a good model organism for other eukaryotic organisms. I have been having a problem with certain groups of study plants. I ordered a batch of seeds from one of the biological supply companies and received them a few weeks back. I planted them all in the same soil, under the same conditions, and they all started to grow. This is when the problem started. I noticed that some of the plants looked different from the “normal” plants. It looks like I have a whole bunch of plants that are not “normal.” In science we call the normal plant that you might find in nature “wild type.” The plants that I have been growing are not the wild type that I ordered. All of the plants are definitely Arabidopsis but I can’t really figure out what is wrong with them. I was hoping that you might be able to take a look at them and identify the problems. I sent along a number of plants for you to look at. I also sent along seeds I obtained earlier that are confirmed to be wild-type plants for you to compare them to.

           If you could take a look at the wild type plants, sketch the plant, take measurements of the parts of the plant, make general observations and use that data to write a description of the plant. Then do the same for each group of non-wild type plants.   Use your data to write back to me explaining what is going on. In your letter, include an explanation the difference between each non-wild type plant and the wild type. If you can, include a hypothesis about what might cause the problem that you observe. For example, if the plant is red instead of green, perhaps it might use a pigment other than chlorophyll. Also include in your report a description of how the plant might be affected by the differences if it were in the wild. Make sure to include your data with your letter!   Thank you for your help.

Morphologically yours,

Dr. Berkowitz