The quote is misleading. The 2-5% figure refers to what percentage of the genes of modern non-Africans were inherited from Neanderthals, not merely common to both groups through a common ancestor. Most of these genes are inconsequential, as they exhibit very little variation even between species. The wide range in the estimate exists because it was determined by extrapolating from the small portion of the genes which do show variation.
The corresponding value for chimpanzees is 0%, as they are not our ancestors, though we share recent common ancestry.
Comments
The quote is misleading. The 2-5% figure refers to what percentage of the genes of modern non-Africans were inherited from Neanderthals, not merely common to both groups through a common ancestor. Most of these genes are inconsequential, as they exhibit very little variation even between species. The wide range in the estimate exists because it was determined by extrapolating from the small portion of the genes which do show variation.
The corresponding value for chimpanzees is 0%, as they are not our ancestors, though we share recent common ancestry.