Lost in Translation

I love teaching biology.  My one problem with high school science is that we are forced to simplify our topics so much that it sometimes feels like I am lying to the students just to help them understand.  Right now, I am teaching genetics and discussing dominance and independent assortment.  In the next chapter, I will break all of the rules of genetics that I just taught them.  Most genes do not have a simple dominant or recessive allele and genes located on the same chromosome are linked together in nature and in the statistics.  


In DNA, the story is far more complicated that time and End-of-Course Test will allow.  Our version of protein synthesis presents as follows:  DNA holds the code for making proteins which is transcribed into mRNA and taken to the ribosome to be translated into an amino acid chain.  However, this process skips a few facts and steps which I think makes the topic even more intriguing.  To be honest, I usually try to mention these interesting parts to the students- knowing that some will neither care nor understand, but maybe one or two will wish to learn more.  


Scientific American posted an article challenging my simplified version of protein synthesis.  In the DNA, some stretches do not actually code for anything.  When the mRNA begins transcription, segments called introns must be removed through RNA splicing.  Only segments called exons carry information.


Now researchers find that mRNA even makes edits to the code after splicing- meaning that RNA itself can edit the DNA code and make a slightly different protein.  This means that even organisms with the exact same DNA (clones and twins) can make slightly different proteins through RNA editing.  While our DNA is 99.9% the same, maybe our RNA makes us slightly more different than that.  To add a greater impact, this process has been implicated as a possible cause for ALS and Epilepsy 1. 


Sadly, high school textbooks, curricula, and state tests continue to sterilize biology to the lowest common denominator.  Hopefully, I can teach them the basics and with brief asides to the amazing nature of biology I can show science for what it is- a changing, complex network of paradigms constantly at risk of collapsing under new data.