Sir Martin Evans

Today the National Portrait Gallery in London unveiled this painting of Nobel winner Sir Martin Evans (2011) by David Cobley. Sir Martin was the first scientist to isolate and identify embryonic stem cells, back in 1980. The artist posed his subject looking at cultures in a petri dish, against a background of writing from Sir Martin's notebook, to recreate that eureka moment of discovery. Sir Martin won the Nobel Prize for Medicine in 2007.
Update: I've posted a better graphic of this painting.