A trivial genetic effect but massive cultural consequence

In yesterday's post, I think that future generations would, as time passed, find it very difficult to believe that the place had really been as powerful as it was represented to be. I quoted Thucydides to the effect that sometimes there is little correlation between the material evidence of a culture and the consequentiality of that culture. 

Today, from The Sun Never Sets on the Anglo-Saxons (part 1) by Razib Khan, there is something similar.  

A generation ago, researchers were focused on maternal and paternal genetic lineages from contemporary populations, looking at mitochondrial DNA and Y chromosomes. Oxford geneticist Bryan Sykes’ 2006 work Saxons, Vikings and Celts was a classic attempt to map modern genetic distributions onto past historical events. Today, the cutting edge of historical population genetics is analyzing ancient-DNA samples, from the famous Mesolithic hunter-gatherer known as “Cheddar Man” of Somerset, England, who died 9,000 years ago, to Anglo-Saxon era warriors buried in 700 AD. While DNA samples from these earlier eras attest to massive genetic transformations, the last invasion of Britain: the Norman conquest of 1066 AD, turns out to have been absolutely trivial demographically. Still, these French-speaking descendants of Norse raiders from across the Channel exerted a massive cultural and historical influence on England, creating the modern English language by grafting 7,000-some commonly used French words from their lexicon onto a Germanic substrate and establishing the contours of the English nation-state through a program of centralization and documentation that began with the famous Doomsday Book.