Here’s one from the latest issue of The Scientist (emphasis added!).
Two hundred years after the birth of Charles Darwin, scientists are exploring one of the central questions of evolution: When organisms become more complex, by adopting the fittest traits for their environment, do those traits place constraints on further evolution? In other words, can complexity slow down the process of evolutionary change? ANDREA GAWRYLEWSKI visits scientists performing an ambitious experiment – involving at least 4,000 mice in the last several years alone – as they set out to find an answer.