Wednesday, 27 February, 2013
Reading the genetic code 2.0
The base sequences of our genes code for proteins, but which genes are expressed in any given cell is partly determined by chemical modifications of these bases. A new study reveals how proteins read and rewrite this “epigenetic” code.
The biological characteristics of all organisms are determined by the order of the chemical bases in their genes, which specifies the kind of protein synthesized in their cells in accordance with the genetic code. Four types of bases are found in all genomic DNAs – adenine, guanine, thymine and cytosine. Moreover, generally speaking, all the cells in an individual contain the same complement of genetic information. So cells also need a second layer of information that controls which genes are active at any time. This “epigenetic” code enables different cell types to express the genes that are essential for their specialized functions.