Even the researchers could hardly believe the findings: 23% of Latin America’s urban population could be descendants of Conversos – Spanish Jews forced to convert to Christianity
For centuries, the Americas – the New World – were a place of refuge for people fleeing the Old World. It offered them the chance to start a new life far from the rules and restrictions of life in Europe. The continents of North and South America were “discovered” by Christopher Columbus, after being dispatched on behalf of King Ferdinand and Queen Isabella, in 1492 – the same year the Spanish monarchs declared that all their country’s Jews must either convert to Christianity or be expelled. It’s no surprise, then, that many of those who immigrated to the Americas were Spanish Conversos, the “New Christians,” who had given up practicing Judaism under duress but still sought to escape the terror of the Inquisition.
Estimates still vary as to how many of these New Christians crossed the ocean. A study published this month in the scientific journal Nature Communications presents an extensive analysis of the genetic history of Latin Americans, and finds that nearly one-quarter have significant genetic roots linking their family to the southern and eastern Mediterranean basin, including to the Jews of Spain. The authors of the study say this is a much more widespread phenomenon than previously thought, and note that the genetic presence of descendants of the Conversos is even more prominent in Latin America than in Spain and Portugal.
Margalit Bejarano of the Hebrew University’s Spanish and Latin American studies department, who was not involved in the study, explains that immigration by New Christians to America began while Spain was building its colonial empire. These converts were legally prohibited from emigrating, but the law was not always enforced. Yet one consequence of the ban is that there is no consensus today as to how many of them did in fact migrate.
“We were not surprised by the presence of Sephardic ancestry in Latin America, since historical documents hint at a possible migration of Conversos, despite records being scarce,” says Dr. Kaustubh Adhikari of University College London, a statistical geneticist, and one of the study’s lead authors. “We were surprised, however, at the broad extent of its presence, as there was no previous indication of this broad magnitude. We thus performed extensive tests to verify that what we observed was not some mere artifact of our analysis.”
“Not all of those New Christians were crypto-Jews,” says Bejarano, in an interview with Haaretz, adding that some Spanish Jews genuinely embraced Christianity even as others continued to observe some of the Jewish commandments in secret. But even in the New World, those who fled the Inquisition weren’t necessarily safe. Agents of the Spanish Inquisition arrived in the Americas too, and secret Judaizers who were caught were burned at the stake. In 1570, offices of the Inquisition were opened in Mexico and in Lima, Peru; in 1603, a third was opened in Cartagena (in modern-day Colombia). The agents would roam the streets of the colonies, urging locals to denounce any neighbors whose customs suggested that they were crypto-Jews. The fate of secret Jews in the Portuguese colonies wasn’t much better. The Portuguese Inquisition did not have an outpost in Brazil, but its emissaries came from Lisbon to search for Jews who were concealing their religious practices, and anyone who was caught was sent to Portugal to stand trial and sometimes subjected to auto-da-fé as well.
The stories of some of those who endured such a fate were recorded by contemporaries and later became well known. One such person was Francisco Maldonado da Silva, who was burned at the stake in Lima in 1639. His story was recorded by another Converso, Isaac Cardoso, and published 40 years later. Cardoso describes what became of Maldonado: “This great interpreter of the Torah, who was imprisoned for 13 years and did not consume meat in all that time but only a bit of corn flour… He grew his beard and his hair like a nazir [Jewish ascetic] and circumcised himself with a knife… He changed his name from Maldonado da Silva to Eli Nazareno… The theologians and agents of the Inquisition summoned him many times to persuade him to abandon his faith, but he debated with them in writing and verbally. He wrote many essays in his cell, having put together used pieces of paper that wrapped items he requested.”
Another famous Converso who was a victim of the auto-da-fé was Luis de Carvajal, a Jewish trader who was arrested around 1590 in New Spain (later Mexico). In his cell, Carvajal wrote a memoir that is considered the first written record of Jewish life in the Americas. In his diary, whose original manuscript was missing for years, although found and returned to Mexico last year, he calls himself Joseph Lumbroso (“illumined one”) and describes how he learned from his father that he was Jewish, how he circumcised himself (with an old pair of scissors) and how he began secretly observing the Jewish commandments and trying to convince his brothers and sisters to return to Judaism. The Inquisitors released Carvajal from prison for a time, perhaps so they could track him and thus find other individuals practicing Judaism in secret. During this time, he managed to complete his memoir, before being imprisoned again and burned at the stake on December 8, 1696, at age 30.

Most of the Conversos and their descendants integrated into Latin American society, and were distinguishable only by certain family traditions that recalled Jewish practices, and that differed from those of their neighbors. It wasn’t until the 20th century, says Bejarano, that people in various parts of Latin America began to associate their family traditions with Jewish roots.
In the realm of science and academia in general, the history of Spanish Conversos in Latin America is an increasingly popular subject of study. Dr. Shai Carmi of the Hebrew University, an expert in population genetics, says that previous research conducted with small samples found genetic links between Latin Americans and Sephardi Jews. In research on genetic diseases prevalent among Ashkenazi Jews (who share certain mutations with Sephardim), for example, mutations that are virtually nonexistent in other populations have been detected in various locales in Latin America.
Genes and migration
The study reported in Nature Communications, which involved more than 6,000 subjects from Mexico and further south – as well as more than 2,000 subjects from around the world who served as the “source population,” for the sake of comparison – provides a much more accurate and detailed picture than was previously available. Carmi, who did not participate in the study, but is familiar with its result, explains that the method used by the researchers was based on the same genetic principles used by companies that analyze individuals’ genetic origins, but with the addition of advanced statistical tools that make it possible to home in to a very high degree on the geographic origin of each part of the genome.
Adhikari notes that the study does not reflect a representative sample of all Latin Americans because it focused on subjects who live in urban areas (near the universities where the research was conducted). “Given how heterogenous Latin American countries are, it is not appropriate for us to over-generalize and assign a single number [percentage] to the overall population of Latin America. For example, the Andean residents of Peru have much lower non-native ancestry, and thus lower Sephardic ancestry as well, if any. Thus the sentence can perhaps be modified this way: Almost a quarter of the Latin Americans studied have Jewish roots,” he says.
Generally, researchers focus on a very small part of the genome, which is known to vary significantly between different people (99.9 percent of the genome of any two people is generally identical). The researchers say the advanced statistical methods they used enabled them to achieve a very high level of geographical resolution – i.e., to differentiate between a genome typical of northern Spain, as opposed to southern Spain, and to follow the process by which the different populations settled across Latin America, which is in the main congruent with the historical record.
One of the most important findings concerned the relatively large proportion of subjects with Spanish-Jewish genetic roots specifically, or from the Mediterranean basin generally. According to the study’s authors, 1 percent of the Brazilian subjects, 4 percent of the Chileans, 3 percent of those from Mexico and 2 percent of the Peruvians were of Jewish or North African-Eastern Mediterranean descent. The study’s authors say that at least 5 percent of the genome that originates in these areas was detected in 23 percent of all the subjects. Among that 23 percent, 12.2 percent of the genome, on average, had a non-European Mediterranean origin, and about two-thirds clearly showed Spanish-Jewish descent.

The study also found that in the case of 19 of the 42 subjects for whom more than a quarter of their genome indicated non-European Mediterranean origins, the genealogical information they provided (as far back as their grandparents) suggested that there had been migration in earlier generations. But for the rest of the subjects with Jewish roots, no genealogical information was found that indicated migration occurred in the past 100 years. Moreover, the genetic analysis of the origin of these roots indicates that the migration event paralleled the appearance of other genetic sources from the Iberian Peninsula – i.e., showing that (Converso) Jews arrived with other Spanish and Portuguese citizens when the Americas were settled in the 16th and 17th centuries.
In 16th-century Spain, there was also a significant Muslim population that converted (by coercion, or otherwise) to Christianity. But the data from the new study indicate that most of the “New Christians” who immigrated to the Americas were Jews (even though they made up a smaller percentage of the population in Spain).
Bejarano says that this result agrees with historical findings. “We don’t really have evidence of persecution by the Inquisition of secretly practicing Muslims in the Americas,” she notes, even though crypto-Muslims were persecuted in Spain.
The study under review did not, however, focus solely on the Jewish background of Latin Americans. The researchers also took a bold look at the connection between certain genetic heritages and external physical characteristics, some quite surprising. For example, they found that in a mixed population with a higher rate of northwestern European roots, skin color was lighter on average. The researchers also looked at two population groups in which clear genetic differences were found – one group related to the indigenous Mapuche people (who are native to Chile and southern Argentina) and the other related to inhabitants of the central Andes. The study revealed that, in addition to having a different genetic profile than the residents of the Andes, these descendants of the Mapuche also have flatter and broader noses. They ascribed this to evolutionary adaptation of life in the Andes at relatively high altitudes where the air is thinner.
For his part, Adhikari notes that since the rate of Jewish genetic origin was relatively low, the tools used in the study were not sufficient to link Jewish roots with any physical characteristics, but, he says, “This is a very interesting topic though and we hope to come back to it in future studies.”
Despite the greater precision of the new findings, Carmi warns against taking the numbers cited by the researchers at face value, adding, “It’s hard to accurately gauge percentages.” However, he says that the study does appear to support earlier data and that its very broad scope (thousands of subjects, each with a detailed genetic and genealogical profile) enhances the significance of the findings. Perhaps the study, yet another example of the use of genetic information as a means for deciphering human history, will spur people throughout Latin America to search for their Jewish roots.