Janet Kelso, a computational biologist at the Max Planck Institute, told Science that this bottleneck concept may not be as widespread as the authors believe, saying that the genetic signals for it are strong only in present-day African populations. This means that any potential bottleneck would have likely been limited to certain ancestral populations. The conclusions, she says, “though intriguing, should probably be taken with some caution and explored further.” There was “a pretty much unanimous response among population geneticists, people who work in this field, that the paper was unconvincing,” Aylwyn Scalley, a Cambridge University human evolutionary genetics researcher, told AFP