How should scientists navigate the ethics of researching ancient human DNA? (2023)

The 2022 Nobel Prize in Physiology or Medicine drew attention to paleogenomics, the sequencing of DNA from ancient samples. Swedish geneticist Svante Pääbowon the coveted prize"For his discoveries about the genomes of extinct hominids and human evolution." In addition to sequencingNeanderthals-Throughand identify a previously unknown early human namedDenisova, Pääbo also discovered that the genetic material of these extinct hominids had mixed with our owna wise manafter our ancestor migrated from Africa about 70,000 years ago.

The study of ancient DNAIt also shed light on other migrations, as well as the evolution of genes involved in regulating our immune system and in the origin of our lactose tolerance, among other things. The research also raised ethical questions. Clinical research involving living subjects requires informed consent from participants and compliance with federal and institutional regulations.

But what do you do when you're looking at the DNA of people who died a long time ago? This is going to get complicated, says the anthropologistAlisa Bader, co-author of a paper on ethics in human paleogenomics in 2022Annual Review of Human Genomics and Genetics.

"Consent takes on new meaning" when participants are no longer there to make their voices heard, write Bader and his colleagues. Instead, scientists must self-regulate and navigate with sometimes conflicting guidelines, some of which prioritize research results; others, the wishes of descendants, even from distant and local communities. There are no hard and fast rules, says Bader, now at McGill University in Montreal, Canada: "We don't necessarily have a uniform field standard for ethics."

Take, for example, research at Pueblo Bonito, a massive stone house in Chaco Canyon, New Mexico, where a community thrived from AD 828 to 1126 under the rule of ancient Pueblo peoples. In the late 1800s, archaeologists from the American Museum of Natural History began excavating there and found over 50,000 tools, ritual objects, and other objects, as well as the remains of 14 people. These human bones remained stored in boxes and crates for study by non-indigenous researchers. Recently, an investigation team extracted and analyzed his DNA. The study, published in 2017, proposed an exciting discovery: the remains found in Pueblo Bonitoonce belonged to a matrilineal dynasty, and leadership in Chaco Canyon was likely passed down a female line that lasted for hundreds of years until society collapsed.

But the investigationprovoked heated ethical debates. Several anthropologists and geneticists,contain worse, criticized the study for the lack of tribal consultation: the Puebloan and Diné communities that still live in the area were not given permission to carry out the research. Critics also cited the inhumane language (such as "skull 8" or "burial 14") the authors used to describe Pueblo ancestors and warned that controversy would increase distrust of scientists.

bader spokeknown magazineabout what we can learn from ancient DNA research and why considering the ethics surrounding it is such an urgent task for the field. This interview has been edited for length and clarity.

What is Ancient DNA? And where can we find it?

Well, ancient DNA is DNA that has been preserved for hundreds or thousands of years. And it can come from humans, animals, plants, microbes, viruses, bacteria.

A simple explanation would be "DNA from non-living beings". We have woolly DNAmammoths, we have ancient DNA from Neanderthals, and we have DNA from more recent human ancestors. So it's a huge range.

If we talk about human DNA, we can get itteeth, bones, hair. We think of coprolites, which is poop. We can get it from something someone has chewed. Any way to leave your DNA now as a living human being can also be preserved for the future.

With the development of next-generation sequencing technology, research on ancient genomes of people of our ancestors has increased dramatically, from very few published before 2009 to over 1,000 by 2017. What can we learn from looking at human genomes? ?

Oh, there are many different kinds of questions that we can address by looking at human ancestral DNA. We can see how close or far apart continents have been connected over time. We can see population movements. We can see how people and their environment interact.

But I think it all boils down to understanding a little more about what makes people who we are today. Ancient DNA simply uses a genomic perspective to understand what happened in the past to shape who humans are today.

You tried this with your own research too, right?

Yes, part of my family is Tsimshian from Southeast Alaska. I grew up in Washington state. But when I was a kid, and still am today, one of the things I really enjoy doing to keep my family together in Alaska is spending my summers fishing. Last summer I went fishing with my grandfather, uncles and father.

This has influenced my current research, which reflects on how traditional foods like salmon in my family shape people.microbiome springs, the bacterial community in our mouth. And there is research showing that these bacteria can affect our health outside the mouth. If they become unbalanced, they can cause problems in other areas of the body. You can also support your health.

My research examines the relationship between traditional foods in indigenous communities in the Pacific Northwest, primarily Alaska and British Columbia, and how they can support biological resilience and health in these communities. In short, to understand how our diet can affect our health at a microbial level.

And you're also studying the oral microbiome of Tsimshian ancestors.

Yes, we compare the microbes we found in our ancestors' mouths with the microbes of future communities and try to answer what do people eat today, what did ancestors eat in the past, how has it stayed the same, how has it changed? that over time and then how that correlates with the microbiome.

When scientists look at the DNA of living people, some kind of institutional committee reviews these projects to make sure they are being conducted ethically. What happens when the people you study are long dead?

The idea of ​​consent and what it means in the context of ancient DNA research is a major challenge in this area. The ancestors themselves cannot consent or withhold their consent to research, as can a living person who decides to carry out genetic research. We don't have a good way to do this with ancestors.

There are many different approaches researchers are taking to this, although I would argue that the one that shapes my own research practice is what we call collaborative community research. Here, descendant communities replace ancestors, and this is in part because ancestral data can influence these modern communities.

In what way exactly?

Well, we can't really pretend that ancestors only exist in this prehistoric or historical bubble and that understanding or learning new things about them has no impact on people alive today.

Of course, these things can tell us a lot about a particular group of ancestors, but they can also be part of the history of living communities. For example, there are researchers who analyze the relationship between communitiespopulation storiesand migrations and movements.

How do you approach your research in this area and with the communities involved?

My approach is to build the relationship with the community as a research partner. So I don't go there just to ask permission.

For example, for one of the churches I work with, I went out and performed and held church meetings. I talked about my research background and the things that interested me, but I also heard about the types of research that interested them. We were then able to discuss what methods could be used to explore these shared research interests and agendas. the project together. I received formal permission to go to the museum where his ancestors were, so that I could see them and take samples from them.

I've provided updates on where we are in the investigation process. This was pre-Covid, so I went out every summer to provide updates. And when we started getting data from those analyses, I interpreted that data with the community. Instead of presenting like this, you know, “Here are the results; That's what the science says,” I said, “that's the data, that's how we generate it, that's how it's often interpreted. How should we think about this in the context of community history and community knowledge? This improves scientific results.

Has being Tsimshian and knowing the values, culture and traditions of the community helped you?

I think the biggest impact it has had is that it has shaped how accountable I hold myself to my community research partners. So when I work and talk to people, I think, "If someone comes into my family, how do I want them to be treated?" This is having a big impact on the way that I build my research collaborations and also on the way that I've moved away or moved away from some of the dismantling processes where communities are not consulted or treated as a resource, as something that researchers use as necessary.

He also mentioned that researchers can take different approaches to these types of ethical questions. Can you talk about this apparent lack of consensus?

The problem with ethics is that it is culturally constructed. Two different people may have different ideas about what is ethical and what is not. And these ideas can also change over time. I think we're seeing a little bit of that with research.

In the review article, we talk about tensions. Some people really target the research to stakeholders like local and descendant communities and how they affect that. They can also take the approach that research is done for the sake of knowledge, regardless of how or who it influences.

Depending on how you orient yourself to these perspectives, you can change your search practices in targeted ways. But we don't have rules or something that everyone is responsible for. There are no formal consequences if you fail to comply with any of the ethical guidelines, some of which even contradict each other.

I think there are advantages to not having one specific thing because it means you can adapt to different situations. Writing a set of rules also creates constraints. But it also means that people sometimes have a hard time figuring out what to do.

What mistakes were made?

In the North American context in particular, the remains of indigenous human ancestors have been taken from their communities and used as a resource for researchers. Sometimes communities knew this and protested. Sometimes communities didn't even know where their ancestors were from or what they were for.

These remains were collected in museums and displayed in ways that were not approved of or considered disrespectful by communities. And in this museum context, non-indigenous scientists did not necessarily have to go to a descendant community and ask for permission to conduct their research. It simply continued a story of violence, harm and exploitation.

As ancient DNA emerged, the bones and remains of these ancestors became a source of genomic research. But we don't want this damage done by archeological research in general to spread further into genomic research. We want them to stop.

How might this community-driven approach that you advocate enable greater collaboration in research?

Genome data is just one form of information, right? When you think about what makes you a person, part of what makes you who you are is your genes, which come from your family and ancestors. And I think the same goes for paleogenomic research. The genomes we study using ancient DNA are part of a big story.

When you collaborate with communities and include community insights or stories, it enhances the narratives we can tell using genomic information. It can only make things better because we have more depth and more perspective on the story we're trying to tell through genomes.

In my opinion, the people who should have the most say in search should be the people potentially most vulnerable to search. Researchers can do harm by sampling ancestors by preventing communities from granting permission or excluding them from participating in the research process.

In a deeply collaborative approach, communities are our partners. Not only do they give their consent for the collection of ancestral samples, but they also help to shape the research questions. Maybe the methods. They are involved in interpreting the data. Or prepare the results for publication. Of course, it all depends on how much the community wants to be involved in the process or not.

What does it mean for you to think ethically about ancient DNA research?

When I think about what is and is not ethical, I try to think about how the harm has occurred in the past.

So as I think about how I want to conduct my research now, I take responsibility for communities as I do my job. I don't think research is just something value neutral. I try to think about how my research will affect others: who will benefit and how can I avoid harm in the process?

It's that kind of restorative justice approach where you say, "People were excluded in the past and we want to include them as much as we can now to heal that damage." In my opinion, this can be achieved by finding new ways to break down the barriers between who is being investigated and who is doing the research.

known magazineis a journalistic effort independent of Annual Reviews.