Identical, but a genetic twist: all your DNA doesn’t really make you so different

New research reveals that, when compared with non-Roma people, there are more genetic differences in the DNA of Roma people than in those from the most under-represented group in the UK, children of African-Caribbean parents

A genetic breakdown of Roma DNA has found that the most ethnic, but least visible, group on UK streets are far more distinct from non-Roma people than anyone thought.

Researchers at University College London (UCL) have done the first genetic study of the genetic make-up of non-Roma people, then compared them with the DNA of white people, from all ethnic backgrounds, to establish that there are more differences in Roma people’s genes than in any other ethnic group in the UK.

Other countries have also used similar methods to calculate their populations, including Sweden, Spain, the US and Israel.

When they have come to work in the lab, the researchers have been surprised at how similar their findings were to their initial prediction. The UCL researchers, led by Dr Adeline Potgeiter, examined 2,000 people’s genomes at the same time, using next-generation sequencing. They found that the sample included data from people from all three of Europe’s main ethnic groups. The information on ethnic origins was particularly robust in people with one parent from each ethnicity and of Mediterranean origins. It was particularly weak in those with one parent from another ethnicity, or from an ethnic minority whose people had not historically been part of the EU.

The genetic make-up of Roma people can be used as the third measure of ethnicity, after race and belonging, because it is comparable to both. It is also relatively unique because the researchers compared the Roma genetic make-up to the under-represented non-Roma groups in the UK.

The UCL team compared the DNA of each ethnic group against that of 5,092 white, black and black-ethnic-origin UK subjects from among 15,775 total DNA samples, to find that there were between 28.8% and 38.1% more differences between them than there were between non-European, non-African ethnic groups from the UK. The differences were highest for the Roma. For non-Roma, the estimated difference in genetic make-up between Roma people and the most under-represented racial minority in the UK was between 46.8% and 51.9%.

The researchers say that the different distributions of genetic differences between Roma people and non-Roma people in the UK, shown in the graph below, strongly suggest that there are significant differences in the genetic make-up of Roma people. In contrast, there are no difference in genetic make-up between non-Roma and white people in the UK. The range of the largest differences indicates that the genetic differences between Roma people and other ethnic groups in the UK are too large to explain those differences using comparable measures of ethnicity.

The comparisons with non-white, non-European people in the UK confirms that genetic differences between Roma people and non-Roma people in the UK are also large. With the exception of those in the most under-represented group in the UK, all groups in the UK also appeared to be inter-ethnic.

In order to determine the genetic make-up of other European ethnic groups, such as the black people who are from other non-European countries in the EU, the researchers tested for differences in the genetic make-up between Hungarian people, people of Greek, Lithuanian, Serbo-Croatian and Romanian origins, and people of Italian and Portuguese descent in the UK. Their data showed similar patterns of genetic make-up between Roma people and other ethnic groups.

Some in the UK welcomed the findings. Professor Steve Paget, a researcher at UCL and who was involved in the new study, said: “By allowing us to build a much more detailed picture of the genetic make-up of Roma people, this study will help us to understand how to prevent genetic discrimination in areas of health and employment, such as sexual orientation.

“But more needs to be done to help Roma people to dispel some of the misconceptions currently circulating about their origins, like the mistaken belief that they originate from south-east Asia, as well as convince parents and children of all backgrounds that belonging to Roma ethnicity is a positive thing for everyone.”

Previous research has shown that there are problems with DNA tests in the UK, in particular for people with no visible ethnic markers.

• M Hyypia is reporting for the Wired UK staff magazine, by request.

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