Scientists have known for decades that genes can vary their level of activity, as if controlled by dimmer switches. Most cells in your body contain every one of your 22,000 or so genes. But in any given cell at any given time, only a tiny percentage of those genes is active, sending out chemical messages that affect the activity of the cell. This variable gene activity, called gene expression, is how your body does most of its work.
Gene Robinson, of Urbana, Illinois, however, suspected that environment could spin the dials on “big sectors of genes, right across the genome”—and that an individual’s social environment might exert a particularly powerful effect. He was right.
Read the full, original story here: The Social Life of Genes