Monday, 16 December 2013

High speed evolution: Environmental stress triggers genetic variation. HSP90 is the key. UPDATE

New evidence points to a mechanism for fast evolution.  When heat-shock protein HSP70 is depleted during times of stress, orderly protein folding is disrupted and genetic variation emerges rapidly.  The cave fish, Astyanax mexicanus, lost its eyes and pigmentation while acquiring other skills after just thousands of years of cave living. Lab work comparing the cave and the open water varieties pinpointed the role of HSP90. "Because HSP90 governs the folding of the key regulators of growth and development it produces a fulcrum point for evolutionary change." Source at Science Daily News.

Solid ribbon model of the yeast Hsp90-dimer (α-helices = red, β-sheets = cyan, loops = grey) in complex with ATP (red stick diagram).[1]
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.

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