The genetic detectives discovering who we really are

Evolutionary ecology is the study of how species and their environments interact, affecting their respective evolutionary journeys. It’s a highly complex area of research, which can hone in on individual species, or zoom out to look at entire ecosystems, incorporating all of the evolutionary trends at play. To put this puzzle together, evolutionary ecologists play detective, gathering clues from a wide variety of sources including ancient fossils, current day genetics, or from observed behaviour in species. And one species in particular has affected its own evolutionary path more substantially than most over the course of its history: humans.

Scientists at the Human Diversity Consortium at the University of Turku in Finland are doing cutting-edge research on how humanity’s actions have led to the genetic legacies we live with today. “I'd say you could sum up our whole research plan as the co-evolution of genes and culture, in Finnish and Finnic peoples,” explains Ronan O’Sullivan, a postdoctoral researcher with the consortium. “So it's very much looking at evolutionary ecology, but treating culture as an one of the many aspects of human ecology. In a sense, you can view human culture as an extension of the ecology of our species.” By figuring out how we got to this point, the consortium hopes to answer questions around how we can be prepared for future changes in diversity.

“As a kid and a teenager, I always loved being in nature and finding all sorts of animals and plants,” Ronan explains. “But it wasn't until I was in high school when I actually realised that this is a viable career path.” Inspired by the “sheer enthusiasm” of a lecturer during his undergraduate degree in zoology, Ronan became a question-orientated scientist, intent on finding out what nature really looks like. “It's not clean experiments, it's mostly just an absolute mess of everything. And I find it fun sifting through that mess trying to glean a bit of understanding from it all,” he says. 

At the University of Turku, Ronan has a wealth of clues to use to put together a better picture of the true makeup of the people who inhabited this region in the past, and the people that live there today. To do that he has two main areas of focus. The first is the study of ancient DNA of people from the late Iron Age to the early Medieval period. “A lot of the history of Finland for this time is almost apocryphal or legendary,” he explains. “Hopefully with this study, we can add a bit more scientific grounding to this part of history in Finland.” The second area of study is examining patterns found in modern DNA to understand how disease epidemics during the 18th and 19th centuries have shaped modern-day peoples’ genomes. “We can do bioinformatic analyses of modern-day genomes to see if we find signatures of selection around genes that would confer immunity against common, highly communicable diseases that until recently posed a major mortality risk especially for children,” he says. 

Conducting this research requires access to source material, and collaborations with inter-disciplinary colleagues and other world-renowned research institutes. The University of Turku ticks all of these boxes. First, they can access the Finnish Biobank, a centralised collection of health information and biological samples for the Finnish population. Additionally, the consortium has access to data on a whole range of data for many of the provinces of Finland. These data include well-quantified information on the dialects, genetics, demography, disease burden, archaeology, and culture of these provinces. “It's definitely an advantage to work in a country and in a research group with this kind of infrastructure and data”,” says Ronan. He also highlights how he can draw on the experience of co-workers with diverse backgrounds - one is an expert in medical genomics, some are archaeologists, and others work on natural language processing which can help in digitizing and extracting information from hand-written texts. Then there are collaborations with the Max Planck Institute for Evolutionary Anthropology in Leipzig, where researchers extract ancient DNA from archaeological material such as bones. 

Steeped in history, Ronan calls Turku “an archaeologist's dream”, but outside of study it’s also one for nature lovers. “There's this beautiful oak forest that’s a 30-minute cycle from the university,” he says, adding there are also two national parks within two hour’s drive. The city is also the gateway to the Finnish Archipelago – one of the most beautiful in the world. “Whether you're into more city life or more into nature, Turku is a good city because it's big enough that you don't feel like everybody knows everybody else's business. But then it's small enough that you get on your bike and within half an hour you can be in a forest surrounded by no one.”