If we were to walk through the cobbled streets and bustling markets of Mexico City in the 16th and 17th centuries, we would see people from all over the world: Spanish settlers on their way to mass at the cathedral, built on Aztec ruins; Aborigines from different regions of America, including soldiers who joined the Spanish cause; Africans, enslaved and free, some of whom came to these lands along with the conquerors, and Asians who arrived in Mexico in Spanish galleons, some of their own choosing and others as prisoners. All of these cultures met and mixed for the first time in colonial Latin America.
Historical documents describe this cultural encounter, but recently international research teams have contributed to enriching our vision from the analysis of the genomes of modern inhabitants. With the help of sophisticated global genetic databases and statistics, ancestry and population mix can be distinguished more precisely than ever.
The results, made public at a meeting in Mexico city this past week and in a pre-publication, tell us stories from Latin America that had been forgotten or never recorded in historical documents. Thanks to this research, all kinds of hidden stories emerge, from the immigration of enslaved Filipinos to that of former Jewish families banned from traveling to overseas possessions.
It helps us recognize in what ways these little historical experiences and practices left a distinct imprint on our genomes, says Deborah Bolnick, a genetic anthropologist at the University of Texas.
The original plan of Juan Esteban Rodríguez, a graduate student specializing in population genetics at the National Laboratory of Genomics for Biodiversity (LANGEBIO) in Irapuato, Mexico, was to study the most recent threads of the global tapestry that make up the current Mexican ancestry.
Asian ancestry
Beginning in the nineteenth century, many Chinese immigrants moved to Mexico to build railroad tracks in the northern states of the country. Growing up near the US border, Rodríguez knows this story in detail and was interested in seeing if he could identify the genetic contribution of these Chinese immigrants to the modern Mexican population.
But when he studied a database of more than 500 Mexican genomes (initially compiled to carry out biomedical studies) in search of the most common genetic variations in Asian populations, he was surprised. Some people from northern Mexico had a markedly Asian ancestry, but they weren’t the only ones.
Rodríguez found that about a third of the sampled population in Guerrero, a Pacific coastal state approximately 2,000 km south of the US border, also had up to 10% Asian ancestry, considerably higher than most of the Mexicans. And, by comparing their genomes with those of the modern Asian population, he discovered that the former keep a
closer kinship relationship with the people of the Philippines and Indonesia compared to the latter.
Together with his advisor Andrés Moreno-Estrada, a LANGEBIO population geneticist, Rodríguez went to the historical registry to identify who could be the ancestors of these people. In this way, historians dedicated to the study of maritime manifestos and other documents of commercial ships explained that, during the sixteenth and seventeenth centuries, Spanish galleons set sail from Manila to the port of Acapulco, in Guerrero, bringing both goods and people, including Asian slaves.
While historians were aware of this type of trans-Pacific trade, the origins of its victims have been lost to history. Once they arrived in Mexico, they were all registered as Chinese, says Moreno-Estrada, who will present his work to the American Association of Physical Anthropologists (AAPA) at their annual meeting.
African ancestry
Hidden stories of slavery and people who lost their identity upon landing in a country completely different from their own are being discovered. Other researchers study the legacy of another segregated group in colonial Mexico: the Africans. Tens of thousands of Africans, enslaved and free, lived in Mexico during the sixteenth and seventeenth centuries. There were even more Africans than Europeans, and today virtually all Mexicans have about 4% African descent. This percentage is even higher among some communities, explains geneticist María Ávila-Arcos, from the International Laboratory for Research on the Human Genome in Juriquilla, Mexico.
Ávila-Arcos discovered that, among the communities of Afro-descendants in Guerrero and Oaxaca, many of whom remain isolated even today, the individuals present about 26% of African descent, mostly from West Africa.
Other data suggest a strong African presence in colonial Mexico. Corey Ragsdale, a bioarchaeologist at the University of Southern Illinois at Edwardsville, examined skeletons along with a group of colleagues in an attempt to identify dental and cranial features that are typically more common among Africans.
It is estimated by the study that between 20% and 40% of the people buried in Mexico City in the 16th to 18th centuries were of African descent. Africans may have played as fundamental a role as Europeans in shaping the population structure and even in the development of the [Spanish] empire, the scientists explain.
Researchers hope to be able to use the genetic data to trace the ancestors of the participants in the study and to identify specific ancestries from West African communities or regions. In addition, identify significant Asian ancestry in some of the volunteers, possibly a holdover from the communities that enslaved Africans and Asians formed on the Pacific coast.
Some Europeans also brought hidden stories to Latin America
In a prepublication recently posted on the BioRxiv server, it is detailed that genetic data from more than 6500 people born in Brazil, Chile, Colombia, Mexico and Peru were used to identify how native groups contributed to the American gene pool.
This is undoubtedly the most far-reaching genetic analysis of Latin American populations to date,” says Ávila-Arcos. A surprising discovery was that common genetic variations in the eastern Mediterranean region and in North Africa, specifically among Sephardic Jews, are present throughout Latin America, in almost a quarter of all individuals sampled.
The authors, led by geneticists Andrés Ruiz-Linares of Fudan University in Shanghai, China, and Garrett Hellenthal of the University of London, associate a significant part of this ancestry with converts, Jews who converted to Christianity in 1492, when Spain expelled those who rejected conversion.
Converts were prohibited from migrating to Spanish possessions, although some are known to have made their way to America anyway. However, the strong presence of Sephardic ancestry in Latin America indicates that migration was much more frequent than the figures that emerge from the records.
For Ragsdale, this work serves as a reminder that even migrations that scientists consider to be no secret can bring hidden surprises. The way we think of colonization is a simplified way, says Ragsdale. There are certainly many subtleties that we do not even perceive. British ships often harassed Spanish galleons, transporting long-forgotten peoples to Latin America, including enslaved Filipinos and converted Jews.
