The underlying paper lists 3 different hypotheses that could explain the results. 1. Unrelated fragility of this particular sequence in Africans 2. Modifier t

The underlying paper lists 3 different hypotheses that could explain the results. 1. Unrelated fragility of this particular sequence in Africans 2. Modifier theory 3. Having mutations makes future generations more susceptible to nearby mutations. This what the authors are suggesting. There's a sort of soft-assumption in modern biology that mutations are approximately random, which underlies things like the molecular clock. It's well-known to be wrong, but at scale the experimental evidence suggests that it still holds in many useful situations. Combine a paper pointing out a limitation of that assumption with popsci press and you get the breathless headline above.