Troublesome sentence

Paleolithic Europeans seem to have been a homogenous population, possibly due to a population bottleneck (or near-extinction event) on the Iberian peninsula, where a small human population is thought to have survived the glaciation, and then expanded into Europe during the Mesolithic period

This is false. I cannot recall any study which asserts confidently that Palaeolithic Europe was genetically homogeneous. If there is one, it would require in-line citation. I think whoever wrote the sentence has confused themselves. The studies have, rather, shown that Mesolithic Europe became more homogenepus because of population bottlenecking with subsequent expansion. The bottlenecking did not cause a homogeneous Palaeolithic population becuase the events occurred subsequently.