A documentary broadcast this month on Spain’s national television made headlines around the world for its ground-breaking claim that Christopher Columbus was a Sephardic Jew from the Iberian Peninsula, contrary to the widely accepted theory that he came from Genoa, Italy.

A team of forensic experts led by the University of Granada has used DNA analysis to investigate the history of the 15th-century explorer in a bid to end a long-running debate over the origins of the man whose expeditions paved the way for Europeans to to colonize the Americas.

Although the scientific method behind the discoveries has not yet been made public, the history-changing claims contained in the documentary Columbus DNA: His True Origins brought to the fore how DNA may hold the key to unsolved mysteries of the past.

How does “archaeogenetics” work?

Archaeogenetics is the study of ancient DNA, or DNA that is more than 70 years old.

Rodrigo Barquera, an archaeogenetics researcher at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, explained that genetic material is collected from human archaeological samples and then purified and sequenced before being examined.

“The longer it’s been since the person died, the harder it is to find genetic material,” Barquera told Al Jazeera, adding that the conditions under which the remains are preserved also play a crucial role.

The analysis can reveal information about the person’s gender and parentage, as well as any diseases the person may have suffered from. It can also determine which populations are more closely related to the sample and thereby suggest a geographic area of ​​provenance.

What cannot be inferred are cultural elements such as nationality or religion or precise ethnicity.

What was discovered about Christopher Columbus?

The documentary, broadcast on Spain’s National Day, claimed the findings – which have yet to be peer-reviewed – show Columbus was of “western Mediterranean” origin, suggesting a genetic similarity to people who lived in the Iberian Peninsula, where modern Spain is located . .

This conclusion contradicts the widely held view that Columbus was from the Republic of Genoa, a port city located in northern Italy.

The documentary also suggested that Columbus was a Sephardic Jew, a specific population of the Jewish diaspora associated with the Iberian Peninsula.

However, as Barquera said, “there is no gene for Jewishness,” because cultural traits like religion are not contained in a person’s DNA.

The team from the University of Granada, which led the Columbus research, did not elaborate on the scientific method used. This will be revealed when the results are officially released in November.

Barquera, who has no connection to the project, speculated, however, that the researchers may have found a similarity to some traits shared by the Jewish population.

While Jewishness is not a genetic but a cultural trait, they may have had a “cluster” – or group – of Jews to compare the genetic information with.

Even then, he said, “Typically, tests are done with multiple human groups, and they would all show some statistical attraction.” Therefore, it would be unscientific to identify a single affiliation rather than some likely multiple.

Why was the study of Columbus’ remains undertaken and why does it matter?

The provenance of the man who made the European “discovery” of America in 1492 has been much debated.

Francesc Albardaner, an architect and decades-long researcher of Columbus who appears in the documentary, was one of the proponents of a different version of history than the “Genoa theory” that textbooks have asserted for centuries.

“Columbus was a Catalan and the son of a man from the Republic of Genoa and a Jewish woman from Valentia,” Albardaner told Al Jazeera, adding that his conclusions match those presented in the documentary.

Albardaner argues that Columbus preferred to introduce himself using paternal affiliation because of the contempt and persecution the Jews faced at the time.

He added that proponents of the “Genoa theory” were faced with the fact that the documents produced under the reign of Ferdinand of Aragon did not mention the place of origin of Columbus, as was the case at the time.

“When talking about foreigners, the Kingdom of Castile explicitly said where they were from,” Albardaner said, citing as an example documents that recorded the Italian explorer Giovanni Caboto as a Venetian.

“In the case of Columbus, they only state that he is an alien,” Albardaner said, adding that this anomaly has never been fully explained.

The theory that Columbus was born a Jew under Ferdinand would also explain why he was able to become one of the highest civil servants in the kingdom, a position that a foreigner would have been unlikely to hold.

Albardaner added that establishing the historical truth about Columbus’ early life was a consequence. “One little mistake can lead to a whole host of wrong assumptions,” he said, leading historians astray when researching his early years and work.

For example, in a research paper, Albardaner detailed how Columbus’s claim to have visited “all the East and the West” before 1470 – contained in a letter written in 1501 – was rejected, especially by Italian scholars, as invention and vanity.

Albardaner argued that placing Columbus’s life under Ferdinand’s rule would lend historical credibility to his naval service in the Mediterranean and establish that he did, in fact, begin sailing in 1461 or earlier.

What other famous cases of genealogy discoveries have there been?

Researchers are using DNA to unravel the many mysteries that still surround human history.

Several studies have focused on the remains of Neanderthals, distant ancestral relationships with modern humans, to reconstruct how closely related they were to our species and what their social organization looked like.

The fossil of a six-year-old child found at the Cova Negra archaeological site in Valencia province, Spain, excavated in 1989 and examined earlier this year, even suggested signs of compassion among Neanderthals.

Nicknamed ‘Tina’, the child is the earliest known evidence of a person with Down syndrome and has also been afflicted with several illnesses. Researchers from the University of Alcala in Spain concluded that for the child to survive at least six years, the group must have continuously assisted the mother in her daily tasks, showing compassion.

Barquera and his team in Leipzig also worked on the remains of another historical figure, the German composer and pianist Ludwig van Beethoven. “We could reconstruct some of the genealogy, and because the sample was very good, we could even do some testing for health issues and confirm that he had hepatitis B,” Barquera said.

“In the past, we could only rely on what was written, but now (thanks to these technologies) we can confirm or rule out some assumptions,” he added.

“In some cases, we could help build a better picture of specific historical events.”