WALNUT CREEK, Calif. Subtle genetic changes that confer an evolutionary advantage upon a species, such as the dexterity characteristic of the human hand, while difficult to detect and even harder to reproduce in a model system, have nevertheless generated keen interest amongst evolutionary biologists. In findings published online in the September 5 edition of the journal Science, researchers from the U.S. Department of Energy's Lawrence Berkeley National Laboratory (Berkeley Lab) and their collaborators, have uncovered a specifically human 13-nucelotide change concealed in the vast three-billion-letter landscape of the human genome. Their experiments reveal this stretch of DNA to be a recently evolved regulator of gee expression that, when introduced into a mouse embryo system, influence the molecular machinery to yield human limb and thumb development patterns.
The study reinforces the conclusion that certain regions of genomesthose which are conserved across many species over evolutionary time and do not encode genescan have a powerful regulatory influence on gene expression or the production of proteins.
"The study points to how human nucleotide substitutions can alter the regulation of genes in humans distinct from that of non-human primates, such as chimps," said one of the study's corresponding/senior authors Eddy Rubin, Director of Berkeley Lab's Genomics Division and the U.S. Department of Energy Joint Genome Institute. "This highlights a strategy that could be applied across the genome to understand at a molecular level what leads to differences between humans and non-human primates."
The goal of the experiment was not to produce mice with human fingers. Rather, an indirect assay was employed to test the expression readout of a single human genetic fragment and compare it with the chimp version. The strategy, which links a color-inducing reporter gene when expression is activated, turns the targeted tissue blu
|Contact: David Gilbert|
DOE/Joint Genome Institute