In truth a vast library of human genetic sequences was available in digital form, and once they had survived the first few generations in Cradle, and trained hundreds of bright young people to be genetic engineers, they could, in theory, have resequenced the original human race from scratch. This was the sort of thing Eve Moira had done by synthesizing the first artificial Y chromosome. But it was not what they collectively chose to do. That choice was altogether cultural, not scientific. Decisions had been made in the Council of the Seven Eves. Races had been founded that were, by then, several generations old. They had begun to develop their own distinctive cultures. To undo those decisions by reverting to the "rootstock" human race was viewed almost as a kind of auto-genocide. The competition that had developed among the different races rendered it unthinkable. So the genetic records of rootstock humanity were put to work adding a healthy degree of heterozygosity back into the existing races, rather than trying to go backward.