12 October 2012
The results of one of the biggest efforts yet to understand the complexity and meaning of human genomic data were published last month by the ENCODE (Encyclopedia of DNA Elements) consortium.
This impressive undertaking brings new understanding to the functional aspects of the genome and can probably be considered the most significant genomic discovery step since the sequencing of the whole human genome in 2000. The ENCODE project assigned biochemical function to about 80% of the genome, and in particular to elements outside of the well-studied protein-coding regions.
The mapping provides new insights into gene organisation and most of all, mechanisms of regulation. A central goal in biology - understanding the enormous diversity of gene expression in different cell types under various physiological conditions - can be considered partly achieved.
The project yielded invaluable information on the human transcriptional regulatory network with systematic analyses of transcription factors, chromatin structure and regulatory modifications. All these findings shine new light on our concept of the gene.
Some of the newly identified elements correspond to sequence variants linked to human disease, and can therefore guide interpretation of these variations. Genome-wide association studies have previously identified many noncoding variants associated with common diseases and traits. Such variants systematically perturb transcription, alter chromatin states, and form regulatory networks. ENCODE’s results point to the involvement of regulatory DNA variation in common human disease and provide pathogenic insights into diverse disorders.
The publication of such a detailed analysis of the functionalities of the human genome has understandably generated much enthusiasm among scientists and general public alike. Confirmation that a far larger chunk of our genome is biologically active than previously thought has been an exciting discovery and researchers hope the findings will lead to a deeper understanding of numerous diseases.
It is however important to remember, and for the scientific community to clearly acknowledge, that despite these fantastic results it may be many years before patients see any benefits from the project. Better understanding of the functional complexity of the human genome will undeniably lead to improved control of disease and to better treatments, but the road to clinical implications and applications is still long and difficult.