TestMN

Background Information

Objective:  Learn about transposons and discover a brand new one all on your own

Difficulty:  Medium

Estimated Time:  15 minutes

New Programs Used:

Quick Pre-Lecture on Transposons

     Look to the image on the right.  It is a picture of maize, commonly referred to as corn.  Note how there appear to be two types of kernels, speckled and unspeckled.  What do you think has caused this?  If you guessed that the maize is diseased or rotting you are incorrect.  The speckles are caused by transposons, non-coding segments of DNA.  Transposons can be viewed as selfish sequences of DNA that are in a constant war with the coding portions of DNA.  If the coding portions of DNA did not fight back with transposons, the transposons would copy themselves to make the genome extremely long.  Another  bad aspect of transposons replicating themselves is that they sometmes insert themselves in the middle of genes, which causes the genes to often malfunction.  Luckily, there is an ancient immune system in place to fight against the transposons.  Once a transposon is identified by this ancient immune system the transposon is prevented from duplicating itself.

      Going back to the maize example, the kernels without speckles indicates one of two possibilities:  the kernel has no transposons, or the kernel has transposons and they have been identified.  With the information provided so far you are probably thinking that transposons are pure evil, but they aren't.