Method of Silencing Genes

I found an interesting article on the Science Daily website concerning the method plants use to silence genes.  In Biology class we are just beginning to discuss plants and their methods of growth and formation.  I just read a section in our book over the differentiation of cells in plants.  This differentiation is the result of many things including gene silencing.  Each plant cell contains the same genome, but the cells perform different functions.  Therefore, this must be a result of gene silencing, where certain genes are expressed and others are not expressed.  A team from Indiana University was researching how plants cells know which genes to silence.  They observed that unlike some thought, this ability to know which genes to silence is not “hardwired” into their DNA.  In other words, it is not an inherited trait, built into their DNA.  Instead, the ability to silence genes seems to be a learned characteristic, through “molecular memory.”  The genes recognize heritable chemical marks on the genes, and remember to silence or express these based on past experience.  The chemical marks/tags serve as “molecular memory” to help the gene remember to silence these specific genes in future generations.  This was a very interesting article published on March 20, considering we are currently learning about the basics of plant differentiation in class!