Transcription factors boost genetic differences to make individuals unique

The 23,000 protein-coding genes in the human genome can help determine whether a person will have blond hair or black, flat feet or arched. But that's hardly the whole story behind the millions of tiny differences among people. Most of the genome is so-called noncoding DNA, whose role in determining individual differences is only just starting to be understood.

Some of these sequences actually exert a big influence on how genes are expressed in different people, report the authors of a new study, published online March 18 in Science. Transcription factors, proteins that are cued by these noncoding DNA sequences, can bind to different areas that change gene expression, thereby altering how a single gene manifests in different people.