The Romani people—once known as "gypsies" or Roma—have been objects of both curiosity and persecution for centuries. Today, some 11 million Romani, with a variety of cultures, languages and lifestyles, live in Europe—and beyond. But where did they come from?

Earlier studies of their language and cursory analysis of genetic patterns pinpointed India as the group's place of origin and a later influence of Middle Eastern and Central Asian linguistics. But a new study uses genome-wide sequencing to point to a single group's departure from northwestern Indian some 1,500 years ago and has also revealed various subsequent population changes as the population spread throughout Europe.

"Understanding the Romani's genetic legacy is necessary to complete the genetic characterization of Europeans as a whole, with implications for various fields, from human evolution to the health sciences," said Manfred Kayser, of Erasmus University in Rotterdam and paper co-author, in a prepared statement.

To begin the study, a team of European researchers collected data on some 800,000 genetic variants (single nucleotides polymorphisms) in 152 Romani people from 13 different Romani groups in Europe. The team then contrasted the Romani sequences with those already known for more than 4,500 Europeans as well as samples from the Indian subcontinent, Central Asia and the Middle East.

According to the analysis, the initial founding group of Romani likely departed from what is now the Punjab state in northwestern India close to the year 500 CE. From there, they likely traveled through Central Asia and the Middle East but appear to have mingled only moderately with local populations there. The subsequent doorway to Europe seems to have been the Balkan area—specifically Bulgaria—from which the Romani began dispersing around 1,100 CE.

These travels, however, were not always easy. For example, after the initial group left India, their numbers took a dive, with less than half of the population surviving (some 47 percent, according to the genetic analysis). And once groups of Romani that would go on to settle Western Europe left the Balkan region, they suffered another population bottleneck, losing some 30 percent of their population. The findings were published online December 6 in Current Biology.

The researchers were also able to examine the dynamics of various Romani populations as they established themselves in different parts of Europe. The defined geographic enclaves appear to have remained largely isolated from other populations of European Romani over recent centuries. And the Romani show more evidence of marriage among blood relatives than do Indians or non-Romani Europeans in the analysis.

But the Romani did not always keep to themselves. As they moved through Europe and set up settlements, they invariably met—and paired off with—local Europeans. And some groups, such as the Welsh Romani, show a relatively high rate of bringing locals—and their genetics—into their families.

Local mixing was not constant over the past several centuries—even in the same groups. The genetic history, as told through this genome-wide analysis, reveals different social mores at different times. For example, Romani populations in Romania, Hungary, Slovakia, Bulgaria and Croatia show genetic patterns that suggest a limited pairing with local populations until recently. Whereas Romani populations in Portugal, Spain and Lithuania have genetic sequences that suggest they had previously mixed with local European populations more frequently but have "higher levels of recent genetic isolation from non-Romani Europeans," the researchers noted in their paper.

The Romani have often been omitted from larger genetic studies, as many populations are still somewhat transient and/or do not participate in formal institutions such as government programs and banking. "They constitute an important fraction of the European population, but their marginalized situation in many countries also seems to have affected their visibility in scientific studies," said David Comas, of the Institut de Biologia Evolutiva at the Universitat Pompeu Fabra in Spain and co-author of the new paper, in a prepared statement.

Finer genetic analysis of various Romani populations as well as those from the putative founder region of India will help establish more concrete population dynamics and possibly uncover new clues to social and cultural traditions in these groups that have not kept historical written records.