|Solid ribbon model of the yeast Hsp90-dimer (α-helices = red, β-sheets = cyan, loops = grey) in complex with ATP (red stick diagram).|
UPDATE: Another environmental trigger for change, this time in stem cells. A low acid treatment transformed common body cells into a type of stem cell. They call this STAP: (Stimulus triggered acquisition of pluripotency). It's a big deal. Cells are reprogrammed after a short exposure to low ph conditions. They can be cultured from that point to become full-service stem cells. This isn't evolution but it means the medium for expressing genetic change is more flexible.