Image copyright Getty Images Image caption Roma people in Italy.
Scientists have found the DNA of Roma people across Italy to be similar to that of sheep, even after controlling for factors such as race, religion and so on.
The study’s authors say the finding could help to explain a variety of genetic and health differences between the two communities.
However, one researcher said the DNA of Roma people in particular was still not known for sure.
Two of the papers in the Proceedings of the National Academy of Sciences journal are available online.
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Previous studies have shown that Roma people in Italy have a lower than average blood pressure, and have greater body fat than the general population. They have also been linked to higher rates of autism and schizophrenia, and rates of cardiovascular disease.
Dr Francesco Melero, from the University of Milan, and colleagues wanted to see if the Roma population had more in common with sheep than other people.
They compared the DNA of 30,000 Roma people – of whom 9,600 identified as white Italian, 20,500 as Italian Roma and another 13,000 as being other Italian.
For the DNA of Roma people, they used 80,000 genes from sheep, where these genes are inherited the same way from father to son.
The team found that Roma people had many similar genetic variants to sheep genes. This echoed recent work from Germany showing similar patterns.
Dr Melero told BBC News that sheep have high levels of a protein called wegenerin 21.
This is important for making sausage. Dohumins work by docking with genes and triggering the cell to make proteins which are activated by heat and generate a protein chain.
Dr Melero said that based on this evidence, it was clear that Roma people are “greatly influenced by flock-associated genes”.
Using a supercomputer, the researchers found that Roma people were only slightly more likely to have genes associated with the sheep gene.
A panel of 170 genetic tests were used to compare Roma DNA against the most common genetic tests used in large European populations.
The fact that there were no significant differences between Roma DNA and major ethnic groups such as Italians and Basques provided some reassurance, the researchers said.
Speaking to BBC News, the Italian doctor Joan Maria Maria Di Crescenzo, said this research would have no real practical benefit, other than to confirm genes we knew are connected to people of Roma ethnicity.
“The analysis shows something that is shown by the geneticists many times,” Dr Di Crescenzo told BBC News.
“It is that we are not that different from sheep. There are many other things which need to be studied if we want to really know the genetic data of Roma people.”
Dr Di Crescenzo said that it was also not known for sure if there were differences between Roma DNA and that of other Italians.
He said the new work did not go so far as to say Roma DNA was in fact related to sheep DNA.
“It is good we know these are plausible studies,” he said.
“This is also a type of subpopulation study, looking at DNA profiles of people who tend to have exactly the same profile as sheep.”
“Now is not the time to say we know what the DNA is of Roma people. These samples have not been tested. But the data can be used in the future for genetic tests in Roma people. We will have access to the entire genome.”
Dr Di Crescenzo said he hoped that one day genomic research would explain all of the statistical differences between Roma people and the general population.
The authors of the two papers in PNAS acknowledge that these findings do not provide a definitive answer.
Dr Melero, who is a Fulbright Scholar studying molecular biology in Argentina, told BBC News that the genetic profile of Roma people was extremely variable, based on where they were born.
There are also many possible confounds which could make a single genetic profile of Roma people misleading.
For example, genetic studies have shown that there are different alleles associated with the sheep gene. This might mean there are different genes in every Roma person.
The team do now want to repeat their work with different groups of Roma people. They are looking for people who have a genetic profile like sheep and will also have an ethnicity of their own, instead of just Italian Roma.