Taking the measure of DNA evidence

A few weeks back, a story appeared in the science section of this paper with the title “Is distinctive DNA marker proof of ancient genocide?” The theory was proposed by a spokesman for IrelandsDNA, a commercial DNA testing company that also trades as ScotlandsDNA and BritainsDNA. He speculated that copper-mining Bronze-Age warriors had invaded Ireland some 2,500 years ago and all but exterminated the farmers already living here.

The evidence adduced was the prevalence of a particular Y-chromosome DNA marker among men in Ireland today, along with several pieces of archaeology in south Munster, where it is proposed the copper-miners might have arrived, along with that medieval compendium of hoary Irish origin stories, the Lebor Gebala or Book of Invasions.

The story also included balancing comments from Prof Dan Bradley from the Smurfit Institute of Genetics, which were commendably clear and, perhaps, restrained. He described the “genocide” claim as “based on a very strong interpretation of a small piece of a genetic pattern” with “no real scientific evidence” to back it.

Public attention is the life-blood of any commercial company and IrelandsDNA is no different. Technically speaking, it is one of the most advanced genealogical DNA-testing outfits in Europe, and shouldn’t need to attract customers by associating itself with such scientific theories.

The public may gloss over the balancing comments and the reporter’s diligent interrogation of the claims. It was frustrating to see that after a few days the story was still hovering in the irishtimes.com “Most Read” section and had clocked up almost 1,000 Facebook recommendations. There is a deep willingness among some Irish people to believe the worst of ourselves, and this story of genocide in our origins is by now well on its way to becoming part of received wisdom about the Irish past.

It is a shame.