Vulnerability and Power in the Genome

All humans are 99.9 percent genetically identical and no group of humans has a gene (i.e., a coded-for protein) that another group lacks. But we are also 98-plus percent identical to chimps and 99.7 percent similar to Neanderthals. Oh, what a difference that 2 percent (or 0.3 percent) makes!

Imagine a group of humans that had a mutation in the FOXP2 gene—­often called the language gene—­such that this transcription factor (a gene that helps stimulate the expression of select other genes) was nonfunctional. These humans would lack the ability to communicate through language. In fact, this gene’s significance was first discovered through the study of an English family in which half the members across three generations suffered from severe developmental verbal dyspraxia—­they could not communicate orally. This family could be 99.9999 percent genetically identical to their neighbors, but what a huge difference that 0.00001 percent makes.

(from Dalton Conley & Jason Fletcher in Nautilus)

Imagine the selection in the bottlenecks of recent evolution.