In Science this week, a research team led by scientists from the Albert Einstein College of Medicine reports that a genome-wide analysis of 59 humans and 10 chimpanzees shows that the two species have some of the same combinations of polymorphisms. While previous studies had only identified two shared polymorphisms between people and apes, the investigators discovered 125 regions with similar mutations between the two. "In six cases, there is evidence for an ancestral polymorphism that persisted to the present in humans and chimpanzees." The findings suggest that ancient balancing selection help shape human variation and "point to genes involved in host-pathogen interactions as common targets," the researchers add.
Also in Science, scientists from Harvard University and Peking University describe their use of single-molecule fluorescence microscopy to observe the activity of DNA binding proteins, which revealed that specific binding of a protein on DNA is substantially stabilized or destabilized by another protein bound nearby. Through this process, called allostery, proteins can affect each other's binding affinity to DNA and trigger different gene expression levels. The findings offer new insights into gene expression and regulation.