The Genomes of Ancient Britains

I've never been very satisfied with the answers given by DNA testing companies when asked how far back in time assessment of ethnic makeup as FTDNA terms it, ancestry composition as 23andMe calls it, and ethnicity estimate using AncestryDNA terminology, relates to for their autosomal tests. As I understand it they all depend on DNA recovered from living people, mostly those who are thought to have deep roots in an area.
So it was encouraging to see the article "Iron Age and Anglo-Saxon genomes from East England reveal British migration history." It uses DNA from ten ancient skeletons found in
archaeological excavations close to Cambridge, ranging from 2,300 until 1,200 years before present (Iron Age to Anglo-Saxon period). They find today’s British are more similar to the Iron Age individuals than to most of the Anglo-Saxon individuals. Let's hope more studies of this type will eventually allow the companies to refine the estimates and provide more satisfying answers.

Read a preprint of the article at http://www.biorxiv.org/content/biorxiv/early/2015/07/17/022723.full.pdf