Natural selection, genetic drift, and gene flow are the mechanisms that cause changes in allele frequencies over time. When one or more of these forces are acting in a population, the population ...

Genetic welding is the human-mediated version of this: introducing genes that have an unfair advantage when it comes to heritability in natural populations. Because these genes spread easily and ...

But surprisingly, when Schroeder looked at the results for the shape of braincases across the Homo genus, genetic drift appeared to be at play, she reported in 2017 in the Journal of Human Evolution.

He noted that factors like small populations, geographic isolation and the harsh desert ecosystem that produced population bottlenecks favored genetic drift over natural selection in these pupfish ...