Sunday, 3 September 2017


     Since the first development of radiocarbon dating in 1949, the process has been subject to a number of refinements, often termed revolutions. From the outset the method was deemed indispensable in establishing a scientific basis on which to build a chronology of archaeological materials. 

      As some of you will recall, and others read, there were problems. Lots of them. Many of these now appear to have been resolved and additional calibrations incorporated. Yet after nearly 70 years the method continues to be adapted and refined.

     The fashion today seems to be the use of DNA and genome studies, considered by many irrefutable proof of origins, migrations and exogamy, domestication and a plethora of other things. Caveat scientia. 

 Concerns have already been raised by some, Mike Pitts, for example (British Archaeology, Spoilheap, 2017).     Writing in The Guardian recently Prof. John Collis, University of Sheffield, entered the debate. Many of you may not have access to the newspaper, or may have missed it, so I am delighted that John has agreed to his missive being reproduced.


     "DNA testing to determine people’s origins should come with a major health warning as interpretations are based on false scientific methodologies.

     First, there is a confusion between two types of data. Our DNA is what we inherit from our parents and, until recently at least, could not be altered. Ethnic or “racial” terms like “English” are culturally constructed “imagined communities” and can be altered and redefined. Though genes may affect our perception of ethnicity (eg in skin colour) it is not dictated by them.

     We have only a limited amount of information about the genetic makeup of earlier populations, and though this is improving, there will always be problems with small, biased sample sizes and big gaps in the archaeological record due to the skeletal evidence not surviving (destroyed by acidic soils, burial rites such as cremation, or many of the dead simply disappearing).

     Reconstructions of past genetics are based on extrapolation from modern populations but this is highly dubious – the origin of a particular genetic mutation is not necessarily where it is most common today, so even assigning particular genetic combinations to a specific geographical area is problematic, let alone to an ethnic group. This is really the racial thinking of the 1930s with a new technology (see the confused Nazi definitions of who was a Jew, a Slav, or an Aryan)."

Prof Emeritus John Collis, 14th August 2017

     I would also add that the rate of genetic mutation is not yet fully understood and that differing rates are often applied, so it is not entirely surprising that results are rarely consistent, particularly when applied to dating migrations.

     My sincere thanks to Prof. Collis for his kind permission to use this letter. It is a credit to the discipline that such world renowned academics can find the time in their busy scedules to respond to such requests.


Professor John Collis, BA, MA, PhD, FSA, MIFA is recognised as a leading expert on the European Iron Age and also an outstanding excavator. His research ranges across the processes of urbanism, Iron Age commerce, and excavation methodology.
Though he has taken early retirement, he will continue to be closely involved in the teaching and research in the department.
Department of Archaeology, University of Sheffield