Protein evolution is irreversible

In their paper "An epistatic ratchet constrains the direction of glucocorticoid receptor evolution", Bridgham, Ortlund and Thornton show that sequence evolution of glucocorticoid receptor is irreversible. Although they only show it for one protein, it may be a general principle. This means that even if evolution was repeated in exactly the same conditions, a completely different world would result, by chance.

Paul Kammerer

Although I am not a genetics expert, the Science news article "The Case of the Midwife Toad: Fraud or Epigenetics? piqued my interest. It would be interesting to see if someone finally manages to repeat Paul Kammerer's experiment.

Modern humans come from East Africa, near de Red Sea

As reported in the issue of Science of 1 May 2009, p. 575

by Ann Gibbons in "Africans' Deep Genetic Roots Reveal Their Evolutionary Story":

The data also confirm earlier research indicating that the source population for the out-of-Africa migration of modern humans came from east Africa near the Red Sea.