The genome is the cell's book of instructions. All the cells in our body contain the same genomic information but each of them "reads" the gene fragments that interest them in order to carry out their function. So, neurones, hepatocytes and cardiac cells are different although their genome is the same. In order to achieve this huge variety of functions from the same genome, the cells employ a mechanism known as alternative splicing.
Very small segments of genes called "microexons" influence how proteins interact with each other in the nervous system, scientists at the University of Toronto have found, opening up a new line of research into the cause of autism.