20 Questions and 20,000 Years (Give or Take) with Jennifer Raff

It's not often a Lawrence local writes a book, her first one, and then watches it swiftly climb to the top of the New York Times bestseller list. KU professor Jennifer Raff experienced that with Origin, and Lawrencians filled the library auditorium when she came to talk about it last month. Given the obvious interest, I was thrilled when she agreed to an email interview.

What follows is part one of a two-part post. Since you've all read Origin by now (or have it on hold), I tried to include both book-related and personal questions. Part two hits the web on Friday.

How did you come to study both anthropology and genetics?

As a kid I was fascinated by archaeology, and never really grew out of it! But I was also exposed to a lot of biology as I was growing up as my mother was in graduate school studying neuroscience. I had the wonderful privilege of being around science professors and research labs for most of my life, and really fell in love with science and biology in particular. After the movie Jurassic Park came out, I realized that my love of biology and archaeology could be combined by studying ancient DNA (though not, of course, from dinosaurs). In graduate school I decided to pursue a double degree in genetics and biological anthropology to develop as broad a knowledge base as possible for working in this field.

I have to ask - which came first, those interests or mixed martial arts?

Definitely my interest in science came before MMA, although I have been studying martial arts in some way or another since I was six years old. I started training in Tae Kwon Do with my sister and father, and eventually my interests broadened. My sister was a very high-level professional fighter in MMA (she was one of the first women in the UFC), and when I started my first postdoc after graduating, I decided to take advantage of her connections and spend a few years on intensive training. 

I was privileged to be trained by some incredible coaches at Gym Jones, at the Bernales Institute, with the Muay Thai legend Sakasem Kanthawong, and I also got to train with some of the best fighters and coaches in the world on my sister’s team. Later I made it to the semi-finals of the Golden Gloves. Today I’m slowly easing back into martial arts after a hiatus spent focused on writing my book, going up for tenure at KU, and having a baby. I’m really happy to be training Brazilian Jiujitsu with the wonderful people at Rivers BJJ here in Lawrence.

I think several facets of your research are unfamiliar to many of us, from the size and duration of the Bering Land Bridge to genetics to the timelines involved. All three are mind boggling. You discuss it in Origin, but could you briefly describe the processes of sampling and identifying DNA?

The process begins with conversations between us and descendant communities. We talk about what kinds of research questions they might be interested in, whether the research questions that we have are acceptable to them, and how they would like us to do this research. For example, are there certain skeletal elements that they would prefer us to sample, are there certain protocols they would like us to follow in respectfully handling the remains, how often would they like to be updated on the project, what involvement would they like to have in interpreting the results, would they like to co-author any research papers, who should have access to the resulting genetic information? It’s only after we figure all this out—a process that can take years of discussion—that we begin the DNA work itself.

These days I don’t get to do much laboratory work myself, the chapter in my book notwithstanding. So it’s one of my students or one of the research staff who does all the actual DNA recovery in our lab. In order to work in this lab, you have to be specially trained in anti-contamination techniques, and you have to wear a full Tyvek body suit, hairnet, gloves, masks, and spray yourself with bleach before moving into the clean areas of the lab. It’s all to prevent modern DNA from contaminating the ancient DNA extractions. DNA extraction takes several days, and it’s really tedious work to recover these tiny, damaged DNA fragments. The researcher then builds DNA libraries and assesses how much of the total DNA extracted from the sample actually belongs to the ancestor.

The amount that’s preserved, if any, determines what we can do with the genome—whether we sequence the whole genome, whether we try to look at the sequence of preselected DNA bases across the whole genome using probes, or whether we can’t do much with the sample because there’s not much DNA present.  Unfortunately, that’s true most of the time, because ancient DNA is so fragile and scarce. But when we do have enough ancient DNA present to get genomic information, we can compare it to other individuals across the world and model population histories using the tools of population genetics.

What are the basic timelines of your studies?

We know that the gene pool of the immediate ancestors of the First Peoples formed sometime around 25,000-20,000 years ago with the interaction of a population of East Asians who encountered a population we call today the “Ancient Northern Siberians.” Immediately following this gene flow event, the ancestors of the First Peoples became isolated. This coincides with the peak of the Last Glacial Maximum, a global climate event in which the northern hemisphere was much colder and drier than it is today, and sea levels were a lot lower because water was bound up in massive glaciers.

One place where these ancestors might have been isolated is the southern coast of what people call the “Bering Land Bridge.” This region was twice the size of Texas, and so I think of it more as a lost continent than a bridge that people raced across. If this model is correct, then people were isolated for a few thousand years in refugia—regions that paleoenvironmental reconstructions have shown to be relatively decent places to live during the last ice age. While they were isolated, this population split into several branches. 

It’s a complicated story, which I go through in the book, but to put it simply: one branch eventually makes its way south of the ice sheets that covered northern North America and peopled the American continents. This may have taken place by boat along the west coast, sometime after 17,000 years ago. Or it could have been earlier, as human footprints at the White Sands site have been dated to 21-23,000 years ago. Genetic evidence and most archaeology favors a ~17,000 year migration, but we can’t currently rule out an earlier one. 

Have you done much field work? Where?

Far less than my archaeologist colleagues, but I’ve worked at archaeological sites in the Midwest, in Belize, and at the Nuvuk site near the Alaskan city on the North Slope that used to be called Barrow (today it’s called Utqiaġvik). I really love fieldwork and wish I could do more of it!

We've found several relatives - not just Neanderthals, but Denisovans, and even Neanderthal-Denisovan offspring. There's also the so-called "Dragon Man" (Homo longi), and "Hobbits" (Homo floresiensis). Do you think there might be others that we've missed? Have the genes of our aforementioned cousins shown up in any Native American populations?

I think that we’re far from having a complete understanding of the genetic variation present in other kinds of humans who were present during our early evolution. We are the only hominins remaining on the planet, but for most of our evolutionary history that wasn’t true. Paleogenetics is beginning to show us their genetic legacies in our own DNA. In the First Peoples, we can see genetic contributions of both Neanderthals and Denisovans that interacted with their ancestors in Asia.

To be continued...

-Jake Vail is an Information Services Assistant at Lawrence Public Library.