1. The work was carried out by a team led by Kirsten Bos at McMaster University, Canada, and Verena Schuenemann at the University of Tubingen, Germany, and is published in this week's Nature.
2. The work was carried out by a team led by Kirsten Bos at McMaster University, Canada, and Verena Schuenemann at the University of Tubingen, Germany, and is published in this week's Nature.
