Perspectives From an Expert on Sea Nomads

Featuring Helen Osborne and Melissa Ilardo

Dr. Melissa Ilardo, PhD, completed her undergraduate degree at Princeton University. She received her masters from the University Hawaii as part of the NASA Astrobiology Institute and then studied at the University of Copenhagen where she received a PhD with Eske Willerslev. She is now adjunct faculty in the Anthropology department at the University of Utah and works for Maze Therapeutics. In her previous research, she identified a previously unknown adaptation in the Bajau Sea Nomads of Indonesia. This unique population has engaged in breath-hold diving to survive off the sea for thousands of years. Currently, she is conducting work to connect this adaptation to changes in red blood cell production while continuing to investigate other diving populations worldwide.

In this podcast, Dr. Melissa Ilardo talks with Helen Osborne about:

  • Experience in studying the spleen size of breath-holding sea nomads
  • The importance of multidisciplinary in addressing interesting questions in biodmedince

Music by Skilsel from Pixabay.

Producer and audio editor: James Aird


HELEN: Welcome to Talking about Blood. I’m Helen Osborne, host of this podcast series and a member of the Advisory Board for The Blood Project. I also produce and host my own podcast series: Health Literacy Out Loud. Today I am talking with Dr. Melissa Ilardo, who is adjunct faculty in the Anthropology Department at the University of Utah. She also works for Maze Therapeutics. As a researcher, Melissa identified a previously unknown adaptation in the sea nomads of Indonesia. This unique population has engaged in breath hold diving to survive off the sea for thousands of years. Melissa is now working to connect this adaption to changes in red blood cell production, and also investigating other diving populations. Welcome to Talking about Blood.

MELISSA: Thank you, hi.

HELEN: I am fascinated with your research, for certainly you are the only person I’ve interviewed about breath hold diving populations. Please start off: how did you come up with this initial research question?

MELISSA: So, it was actually quite different from what I was meant to be working on during my PhD. I went to work in the lab of Eske Willerslev who is a renowned in the field of ancient DNA. I had a wonderful ancient DNA project but then I found out about another group of sea nomadics called the Moken in Thailand. I thought that they sounded extraordinary, both in terms of their breath holding abilities, but also their long history of engaging with the sea. And I just thought as someone who’s always been fascinated by evolution, I thought now here’s a human population that’s just a perfect testing ground for natural selection. And that’s because breath-hold diving can be extremely dangerous.  

HELEN: Wow, can you just make it a little more vivid? I have this image of a movie or a play I’ve seen about breath-hold diving, but what does that mean in real life?

MELISSA: Yea, so these populations, these sea nomad populations traditionally spend their whole life at sea. They’re living in house boats and they’re getting everything need from the water. And they’re doing this largely through breath-hold diving. One of my favorite stories about these sea nomad populations is that often, traditionally when they were spending all their time at sea on house boats, the children would learn how to swim before they learned how to walk because there was a lot more water in their life than there was land.  

HELEN: How long do they hold their breath compared to how long you or I might hold our breath underwater?

MELISSA: It really depends what they are diving for. They are diving very functionally. So if they are diving for something that is only found very deep, they’re holding their breath for a lot longer. Maybe several minutes at a time. Otherwise maybe they are diving more shallow for things like mollusks that they can find in shallower depths. But what’s really remarkable is that they’re really not recovering for very long. They’re actually spending often more time underwater than above water because they just take a really short recovery and they are immediately diving again.

HELEN: That’s absolutely fascinating. You spoke about your interests in evolution too. Whatdid your research find once you decided that this was the population you were going to be looking at? Just a quick take about what you learned about that. Your initial question has to do with evolution and the body. Tell us more.

MELISSA: Yea that’s right, so as I said, I thought maybe evolution was acting in this population. But in order for evolution to act, it needs some kind of phenotype or physical characteristic to act on. As I started looking into the human dive response, and there are several components of that, the heart rate response, there’s a vasoconstrictive response, where your blood vessels are changing to keep you blood closer to the center of your body. And there is this splenic contraction. So, your spleen actually contracts during a dive to get you access to these stored red blood cells. So, I ended up choosing that as the phenotype that I wanted to study. When I looked in this population, I found that not only do they have larger spleens than nearby populations, but we’re able to link that to a genetic change. It seems that they actually evolved to have larger spleens and that may in some way help them to increase their time under water.

HELEN: I continue being fascinated I cannot even come up with other words to describe this. You have learned so much and you know, how did this all happen? How did you go from your initial curiosity and support from your advisor to knowing so much about this? Was this just you all by yourself, or how did you learn about this? Tell us the process.

MELISSA: Yea so I was really fortunate. I started to come up with this question and was guided by my supervisor. I was really lucky. Even as I was interviewing for the position he told me, if you have a really great research idea and you bring it to be and you can defend it, I will support it. And that’s exactly what he did. And he connected with me as well with Rasmus Nielsen, who’s an expert in this field and really just an outstanding and brilliant researcher. And Rasmus was the one who really encouraged me to narrow in on a particular phenotype. And so through that process, I was looking into all of these different physiological components. I was speaking to a lot of physiologists. I was trying to get connected to the populations themselves, which is a really challenging feat. I reached out to basically any anthropologists I could find, including the person that eventually connected me to the population that I worked with – connected me to the person who connected me, a Dutch graduate student who had written a thesis on the anthropology of this population. I was reading anything I could get my hands on, and reaching out to a really fabulous anthropologist at University of Copenhagen who had worked extensively with this population in and around Singapore. The first thing she said to me was you need to learn Indonesian. That’s because these populations tend to be largely marginalized. They’re sometimes referred to as sea gypsies. I tend to avoid that name because gypsy carries the same kind of negative connotation in those populations as it does in the Roma people in Europe, where you have a lot of people saying that they’re thieves, criminals. There’s a lot of negativity around what people believe about these populations. So she was saying you need to learn Indonesian so you can communicate with them directly, and you’re not depending on people who might have biases against them to translate what’s going on.

HELEN: What I’m hearing from you is that multidisciplinary approach to this, so yes you started with academics. That’s what people do when they get their PhD. It seems like it went beyond the science somehow to also include anthropology or maybe you started with anthropology and then went to the physical medicine. You also went into language and had to access this population. How would someone be putting together a project that’s this complicated and this diverse to find something that has lessons for us all.

MELISSA: Yea I really think multidisciplinarity is the key to most research questions. Because, most of the things that we’re finding are not found in a vacuum. You need to understand the cultural context to try to put a date. How long have these people been diving? You need to deeply understand the physiology to know am I looking at the right organ? Am I measuring it in the right way? I spoke to clinical ultrasound technicians to make sure I that was measuring the spleen correctly. You obviously have to incorporate the genetics, but if you’re finding the genetic signal, if I had just looked at the genetics of this population, I never would have known which gene to connect to the spleen. There’s really kind of an obscure connection between the phosphodiesterase we ended up identifying and the spleen, but it’s one that has been really highly significant in terms of trying to understand this physiology. All the physiologists that I worked with, I talked to clinicians about what the implications of this might be. I was once giving a talk to clinicians and someone mentioned to me that people that have their spleen removed are much more likely to die in traumatic car accidents because of that extra reservoir of red blood cells. So, there’s just all kinds of information coming from all these different disciplines. Without them it seems impossible to me to paint a whole picture of such a complicated question. I think any question concerning the body, concerning evolution, concerning genetics requires that multidisciplinarity.

HELEN: You use the word paint and I like that because I think of paintings. They are so multifaceted in all those colors. I’m also thinking of what The Blood Project is all about. And that is about bringing many factors in including humanities, including audio like these podcasts, as well as the physiology, the science, the lab smears, the technology – bringing all of that together to learn more about what makes us human and keeps us healthy or makes us sick. You’ve done that on this very distinct project. Listeners of The Blood Project come from all backgrounds and bodies of knowledge. We have a lot of listeners who are practicing hematologists or clinicians who’ve been doing this for a long time. Physicians who want to know more about blood and what it means in their practice. We also have those considering entering the health fields or those new to it, perhaps in medical school or in the early part of their training as physicians or other clinicians. And we have people like me and many others who are just curious about all this. I welcome from all you’ve learned and all you’ve accomplished. What recommendations and thoughts do you have for each of these audiences based on your really interesting project about breath-hold diving. Let’s start with those who are seasoned professionals. What can they take away and learn from your experience at any level.

MELISSA: I mean I think, obviously it’s slightly different depending on the audience member. My recommendation for everybody would be pretty much the same – which would be talk to each other. Talk to people outside of your discipline. Attend talks that you wouldn’t think you’d be able to understand. Ask questions. Be curious. Look for answers in places maybe you wouldn’t have thought of because we have so much to learn from each other. I think one of the things that happens in academia is that we specialize. You have to get really good in your field. What happens in that process is that we end up in this silo where we’re not even aware of what’s happening in other fields. There are papers that are being published by members of other fields that we’re not even hearing about. We just need to open that communication and you know clinicians speaking to theoretical evolutionary biologists and things like that. Because you never know where an insight is going to come from that’s going to bridge those two disciplines and result in a … in terms of our understanding of the body. Being curious and stepping outside your comfort zone in terms of learning something new, which obviously it sounds like your audience is really interested in which I think is outstanding. You know picking up a book from a different field and just not being afraid to not know the answers and to ask someone because chances are there is someone out there who has the answer you are looking for and has curiosity about the things you know. I really think if we just all communicate more and more of this multidisciplinary interaction happens, it will be really good for science and clinical care.

HELEN: You stated it so well. I also just wonder when I think of the audience for all the different parts of life and career that we are at, is it harder when someone’s at the early stage of their career to ask questions and reach out and be curious when they’re still learning the fundamentals? You were so supported in your research by your advisors in doing just that, but someone, let’s say studying medicine, do you think that would be harder to do, or do you think your lessons apply from the beginning?

MELISSA: I think they apply from the beginning and I think part of the evidence for that is that if you look at some of the Nobel Laureates and the really outstanding scientists, a lot of times their innovation come really early in their career. I think part of the reason for that is that early in your career, it’s easier to not know and admit that you don’t know, and to be open to being wrong. I think that’s the hardest thing, especially as we become experts in our field. It’s a lot harder to go ask a question that feels really naïve. I think it really can apply to anyone at any stage in their career. I think going into it with humility, being aware of what you don’t know, but expressing your curiosity and your respect for whoever it is that you’re asking the question to. I think all researchers appreciate that because we’re all really excited about the things we know and really excited to share with others. I think it’s harder for people later in their careers sometimes to ask questions because we don’t want to feel stupid. For anyone early in their career, like you said, I was really well supported in mine and encouraged to ask these questions and seek out the right people but I think even if you don’t have that, I mean finding a mentor for yourself, just reaching out to someone and very often I think people are willing to help support people because like me, they have been supported along the way in their career and are really happy to extend that same support to anyone else. I’m thrilled when young researchers write to me with questions or ideas or anything like that.

HELEN: I’m also speaking as a person who represents that audience of people who are curious. You give me inspiration too and I think that it’s lessons that hopefully all of us can apply in our lives to be open to innovation, to be open to being wrong, to be curious, to ask questions, and look out at that big wide world, including in the ocean, to see how we can move ahead and find out place in this world. Melissa, I thank you so much for sharing your journey with us, your research journey, your knowledge journey, for sharing it with us and inspiring us all to go forth, be curious, learn, and teach others about what we learn. And that’s all on top of all you’ve learned about blood, physiology, and anthropology. Thank you so much for all you’ve done, all you’ve shared, for the way you inspire each of us no matter where we are in our career and our interests, for letting us know about the importance of being curious and open to learning. Thanking you so much for being a guest on Talking about Blood.

MELISSA: Thank you, it’s been my pleasure.

HELEN: As we just heard from Dr. Melissa Ilardo, it’s important to consider many facets of how we learn about people, and health, and blood. That includes certainly taking an interdisciplinary approach. To learn more about The Blood Project and explore its many resources for professionals, trainees, and patients, go to thebloodproject.com. I invite you to also listen to my other podcast series about health communication. To do that, go to healthliteracyoutloud.com. Please help spread the word about this podcast series and the big Blood Project. Thank you for listening. Until next time, I’m Helen Osborne.