Edmund Gilbert reports
A new study, led by Prof. Gianpiero Cavalleri at MCT and Prof. Jim Wilson at the University of Edinburgh, has examined the population history of the Irish Travellers and has confirmed that the Irish Travellers share a common Irish origin with the settled Irish population. The work has also for the first time estimated the date which this divergence occurred.
The Irish Travellers are a small nomadic population, making up about 0.6% of the total population on the island of Ireland, or between 29,000 and 40,000 individuals. Within the population cousin marriages (consanguineous marriages) are common, and the population is socially isolated from the surrounding settled Irish population.
The researchers, who also include MCT PhD student Edmund Gilbert, Shai Carmi of the Hebrew University of Jerusalem, and Sean Ennis of University College Dublin, used SNP-array based genotype data to compare the population genetics of the Irish Travellers to neighbouring Irish and British populations, as well as world-wide groups and European Roma Gypsies.
The study found that although the Irish Travellers were genetic closest to the settled Irish population, they showed significant differences. The study also confirmed the lack of recent shared genetic ancestry between the Irish Travellers and Roma Gypsies. The Irish Travellers, therefore, represent a subset of Irish genetic diversity, and the significant differences can be attributed to genetic drift, brought on by hundreds of years of genetic isolation and a decreasing population size. The analysis showed Irish Travellers also exhibit within-population sub-structure with four apparently distinct groups emerging, and interestingly these groups mirror different forms of the Shelta language and sociological groups within the Irish Travellers.
The dating of the origin of the Irish Travellers is of considerable interest, but this is a distinct date from the genetic origins of each population. This study has estimated a time of genetic divergence of the Irish Travellers and the settled Irish population using genomic tracts of shared identity. This method estimated the divergence to about 12 generations (360 years) ago, which is far older than common belief that the Irish Traveller population arose from the time of the Great Famine. The size of the dataset limited the authors to exploring the relatively simple model of one divergence event, future work is required to expand the study to explore more complex demographic models. The Irish Traveller population was shown to have high proportions of the genome where both maternal and paternal copies are identical, at similar levels to other consanguineous populations around the world.
The research was also welcomed by author and Traveller activist, Michael McDonagh said, “As a Traveller who has spoken on the history and identity of Irish Travellers to many groups ranging from children to academics, you sometimes rely on anecdotal information in trying to put across a serious message about Irish Traveller history. I am delighted that now we have qualified evidence that substantiates the argument I have made for many years, which is that Travellers did not descend from the Famine in Ireland. This research allows us to bring Irish Traveller history back many and gives us a factual identity.”