Linking Genetics and Language Evolution with Prof. Sandra Oliveira
Starting this year, Sandra Oliveira has taken on a position as Assistant Professor in Genetic and Linguistic Evolution at the University of Zurich. Her expertise brings a new light to the research of the NCCR Evolving Language.
From biology to language
Sandra Oliveira’s fascination with human evolutionary genetics began during the third year of her biology degree, at the University of Porto, when she took a course on this subject. That interest led her to study the evolutionary history of specific genes, and to reconstruct population histories based on patterns of variation across the whole genome, gradually weaving into questions about language and culture.
“Genomes evolve through a combination of random processes and selection, and the effect of these processes depends on how populations are structured and how individuals mate,” she explains. “How profoundly culture shapes population structure, and human evolution more broadly, often outweighing environmental factors. So, I became increasingly interested in understanding how cultural behaviors, languages, and genes co-evolve.”
Her research is deeply interdisciplinary, combining population genetics, anthropology, archaeology, linguistics, and computer science. “For me, working across disciplines is great, because I’m very curious and interested in many different things,” she says. But sometimes, communicating effectively between disciplines is challenging: “We want to dive deep into specific aspects of our field, yet we also need to keep a broader perspective so that all collaborators stay on course.”
Professor Sandra Oliveira © University of Zurich
An unsuspected parallel
Culture and genetics are both passed down through generations. Just as genes are inherited from parents, cultural traits, such as language, are largely transmitted by the parents to the children. “Even though culture can be transmitted in more complex ways, we still observe some striking parallels between the two,” Sandra Oliveira explains. Sometimes this link is even causal: “For example, in regions where milk consumption is a common cultural practice, genetic variants that allow adults to digest milk are more frequent in the population.”
The researcher previously explored this connection and the role of other cultural practices in populations from the Namib Desert in Angola. “One aspect that struck me, was how the maternal, but not the paternal, genetic structure was clearly matching these groups’ matrilineal clan system,” she explains. “Another was uncovering a deeply divergent ancestry component in their genomes.” Although these populations now speak Bantu languages, the Namib Desert was once home to the last speakers of Kwadi, and anthropologists suspected that their genetic origins were highly mixed. Through genetic analysis, Sandra Oliveira and her team were able to sort out the various ancestries composing their genomes, and link them to broader migratory movements across Africa. “We found that the deeply divergent ancestry was the earliest to split from the ancestries found today in groups of hunter-gatherers from South Africa,” she says.
Her work also extends to ancient DNA. During her last postdoc, she analysed a large dataset of prehistoric samples from across Europe to trace the expansion of early farmers during the Neolithic period. Her analysis revealed surprising patterns. “Contrarily to our expectations for a range expansion, in some regions of Europe we observe an increase in genetic diversity compared to that found at the source of expansion, in Anatolia,” she states. “We are still investigating the cause, but admixture with local hunter-gatherers alone does not seem to explain the pattern in all regions.”
Studying language evolution
In the NCCR Evolving Language, Sandra Oliveira will investigate how demographic processes shape language evolution. Her team plans to collect genetic and linguistic data from across Africa. “African populations harbor exceptionally high linguistic and genetic diversity. This diversity reflects their deep and unique population histories, providing excellent case studies for understanding how different evolutionary paths influence language diversification,” she says.
The project uses cutting-edge methods for inferring demography and selection from whole genomes, and combines it with digital technologies for collecting data on languages and other cultural traits, with the involvement of the communities. To better understand how populations change over time, and what role migration and admixture play in shaping languages, Sandra Oliveira plans to jointly analyze genetic and linguistic data with quantitative and model-based approaches.
Joining the NCCR, Sandra can be in contact with experts working across disciplines. “It’s amazing to be part of the NCCR because it allows me to expand my network and to discuss some of the most fascinating questions about human evolution with colleagues who bring very diverse perspectives,” she shares.
