On a hunt for enhancers that could make us human, the authors of this study zoomed in on a genomic region they termed human-accelerated conserved non-coding sequence 1 (HACNS1).
HACNS1 showed statistical signatures of being an enhancer, and also had the most surprising amount of sequence change during human evolution of all the 110,000 such sequences identified in the human genome it was by far the most striking candidate.
Remarkably, HACNS1 was found to play a unique human-specific gene-activating role in a region of the developing limb that eventually forms the junction of the wrist and thumb, and also extends partially into the developing thumb. A similar, though weaker activating role was also observed in the corresponding ankle/foot-forming regions of the developing hind limbs.
Highlighting the practical long-term goal of their joint project, Dr. James P. Noonan, last author and Assistant Professor at Yale University, pointed out, "Insights into human diseases and their treatments are often obtained through studies in non-human 'model organisms' such as mice. However, many human diseases are not reproducible in mice, and some diseases such as Alzheimer's and HIV/AIDS are not even known to exist in chimpanzees, our closest 'relatives'. Moreover, even if a disease is observable in a model organism, inter-species differences often cause treatments that appear to work when tested on, say, lab mice, to fail at the stage of human clinical trials. It is therefore imperative for human medicine that we fill in the gaps between our species and others by comprehensively characterizing human-specific genomic sequences and molecular processes. For this reason, it is imp
|Contact: Cathy Yarbrough|
Agency for Science, Technology and Research (A*STAR), Singapore