2012 Panel Discussion - Questions and AnswersHuman EvolutionWhen will the changes in the genome that occur over a lifetime be characterized? Never, in any comprehensive way. If we try to study trillions of cells, each with its own genome, all embedded within the most complex physical objects known to exist in the universe, we will be defeated. We need the simplifications that underlie all successful scientific practice. Cancer biology is driving serious efforts to understand the evolution of somatic cell lineages. Telomere biology has made modest headway in looking at systematic changes in the genome over time. Success in chipping away at this problem, however, will depend on breaking the question down into manageable chunks. What will humans look like in 3 million years? Where is our evolution heading? We have no idea. Scientists need enough humility to admit what they do not know and have no way of knowing. But how will we recognize the next human species? Speciation is about reproductive isolation. Humans will only speciate if we establish strong reproductive barriers between different groups. Fortunately, the whole sweep of history is going in the other direction. The main point here is that long before we would need to assess whether or not some isolated group of humans was a new species, we would recognize that the pre-conditions of speciation had been met. I can think of three possibilities: (1) Some form of apartheid that persisted for at least thousands of years; (2) Some Frankensteinian experiment on a human sub-population; (3) Space colonization. If and when the next human species arises, I hope it is by the latter mechanism.
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