Fifteen Questions: Andrew Berry on Fruit Flies, LS1b, and Harvard-Yale

Andrew J. Berry received an undergraduate degree in zoology from Oxford University and a PhD in evolutionary genetics from Princeton before arriving at Harvard as a Junior Fellow. He is now a lecturer on Organismic & Evolutionary Biology and the Assistant Head Tutor of Integrative Biology.

This interview has been edited for clarity.

FM: So, what brought you into evolutionary genetics?

AJB: All sorts of factors — it was sort of a conspiracy, actually. My father was this academic scientist. My mother was a medic. So there was biology at home. In the typical, if ghastly, British bourgeois fashion, I was taken out of my natal home and plunked into a boarding school at the age of 13. The school, curiously enough, was Charles Darwin’s high school, so I took science in the Darwin buildings. I had a truly inspirational biology teacher back then. He had made it his business to become an expert in Darwinian thinking. You might say [it was] weirdly over-determined; I had to become an evolutionary biologist of some kind.

FM: What’s the most fascinating evolutionary innovation you’ve either studied or encountered?

AJB: Atavisms, which are traits that are not present in a contemporary organism but were present way back up that organism’s family tree. Here’s a famous example: A whale off Vancouver in the Northern Pacific had two symmetrical appendages sticking out from its rear sides — legs. What’s happened? There was this famous moment about 375 million years ago when [our ancestors] got out of the water, and we got tetrapods and eventually, amphibians and reptiles and mammals. Then, you got a bunch of lineages that decided to go back to the water. The atavism is something that might be a mutation, might be a developmental anomaly, [in which] the signal that suppresses the production of the hind limbs has failed.

FM: Why do evolutionary questions matter to you?

AJB: The evolutionary process is the most beguiling, interesting, and important feature of all biology because it touches everything. You might be a cancer biologist interested in why the cell cycle has been corrupted by particular mutations. But where did that cell cycle that’s been corrupted come from? It evolved. And what do cancers do? They evolve as you try to hit them with drugs. [Studying evolution] is, in a sense, an excuse to study everything.

FM: Your early research focused on adaptive evolution within a particular chromosome of the Drosophila genome — what did this work find?

AJB: We were interested in how we [could] identify the action of positive Darwinian natural selection in DNA. Most natural selection is negative: a new mutation arises, it breaks something that works, [selection] just eliminates it. But what about innovation? That’s positive natural selection, where a new mutation arises and it actually makes the bird fly faster or the whale swim faster. How do we identify those events? A large proportion of the changes are random; they don’t matter. You can’t formally distinguish them between random and adaptive evolution, except in situations where you’ve got a lack of recombination in that region of DNA. Say I’ve got this new beneficial mutation on it. It’s not just the beneficial mutation which will go to 100 percent [in the population]; it’s the entire chunk of chromosome. In fruit flies, chromosome four very seldom undergoes recombination, so it was a good candidate to look for evidence of this “selective sweep.”

And lo and behold, we looked at a particular gene and [found] there were no mutational differences in this huge chunk of DNA across the entire species of Drosophila melanogaster. That tells you that there must have been a selective sweep for an adaptive mutation somewhere on that chromosome. Now [these tools for detecting selective sweeps] are very standard in human genetics.

FM: You arrived at Harvard as a researcher, but nowadays, you dedicate your time to teaching. Why did you make this transition?

AJB: As a postdoc, I met lots of interesting people and had lots of great conversations. But I was never that excited about being in a molecular biology lab. The question was [whether] there was a way I could be involved with science without spending all day pipetting. And it’s pretty addictive, teaching, especially teaching at Harvard, because you get to walk into a room with a lot of smart people who are forced to listen to you. It’s an opportunity to try and convince other people that what you think is important is important.

FM: You help teach one of the largest classes on campus — Life Sciences 1b. What are the particular rewards and challenges that come with teaching at that scale?

AJB: One challenge is it’s sort of depressingly impersonal. The second thing is it’s not my course. [The class] is a prerequisite for basically all the life sciences, so there’s a committee which essentially decides what the content is, and my job is to execute that. That’s not super sexy. The big positive, however, [is that] first-years are qualitatively different from upperclassmen. First-years have not had the enthusiasm kicked out of them. They are just brilliantly engaged and excited and fun to talk to.

FM: What sorts of questions get you out of bed in the morning these days?

AJB: It’s my job to stay on top of what’s happening in science. I can’t just recycle lectures from 20 years ago, so what gets me out of bed is the opportunity to figure out what I should be adding in the next iteration of course X, Y, or Z. That, and the prospect of breakfast.

FM: How would you say your approach to teaching has evolved over time?

AJB: I’ve become more sensitive to the fact that I have one great virtue as a teacher, which is I’m pretty dumb. No, seriously, I’m not only at your level, I am probably slightly below it. So if it’s a complicated idea, I might struggle to understand it. But because I’m struggling to understand it, that means I have to unpack it and lay it out in a way that a complete moron — I’m looking at you, Andrew Berry — can understand it, which turns out to be pretty good for introductory courses.

FM: You like to integrate the history of science into your classes. What value do you think comes from learning about the people and the stories behind the science?

AJB: I believe humans are wired to tell and hear stories. The trouble with a lot of science instruction is there’s no story there. There are all sorts of ways [storytelling] can work in class. If there’s a whole set of experiments that build on each other, that’s a great story arc.

The other way is to incorporate personal stories. We can just dive in and talk about Mendelian genetics, but it’s much more engaging if you can think about Friar Mendel. He tried to take this exam which would qualify him to be a teacher and failed it twice, which is already a wonderful, teachable moment, right? Some of the greatest scientific breakthroughs have been done by people that are on the side, or serendipitously.

FM: You have a particularly strong interest in the naturalist Alfred Russel Wallace. Tell me more about him. Why do you find him so compelling?

AJB: Wallace is somebody who’s sort of famous for not being famous. The reason Darwin published “The Origin of Species” was that he got this letter from this nobody 14 years younger than him who was out collecting specimens in the rainforests of Southeast Asia: Wallace. Wallace sent Darwin a letter in which he basically described Darwin’s theory. Darwin panics, and he and his senior colleagues save face by having the two scientists co-publish a paper in 1858. Then Darwin immediately pumps out “The Origin of Species,” partly to establish his precedent — he’s been working on this idea for a long time. When you Google “evolution,” what do you see? It’s that luxurious, big forehead of Darwin. What happened to Wallace? You might think he was a one-hit wonder. No, he did all sorts of incredibly important science. He was an amazingly progressive thinker.

FM: What common misconception about evolution do you most wish you could dispel?

AJB: The premise that you either believe in evolution or you believe in God. What I want people to be comfortable with is that these are not formally incompatible worldviews. What they are are different worldviews which don’t really overlap. Science is about observation, experiment. Religion is accessed through faith. You’ve got two different ways of viewing the world. They’re both equally valid.

FM: Can you forecast how the human genome might change over time?

AJB: No, not really. Natural selection [depends on] the interaction between the environment and the genome. So if there’s variation for the ability to run fast, and there’s a lot of lions in your neighborhood, then you’ll have natural selection in favor of running fast. You might say, can we predict future environments? I would say no. It’s very difficult to predict anything.

FM: What selective pressures exist at the moment?

AJB: There are people who will tell you that natural selection isn’t occurring in human populations. I’d point to the fact that diseases that used to kill us, no longer kill us. If I’ve got Type 1 diabetes, I’m perfectly capable of having kids and passing on my genes that probably predispose me to Type 1 diabetes. And, hello, COVID. I bet COVID is exercising a pretty major selective event. There’s no question that evolution under natural selection is still going on. Where we’ll end up, I’ll let you figure that out.

FM: Have you noticed any interesting ways that Harvard students have “evolved” to survive this arguably harsh environment?

AJB: Well, no is the answer. It’s actually an unfortunate piece of linguistic confusion. When I as an evolutionary biologist talk about adaptation, I’m talking about the fact that the Galapagos finches’ bills are perfectly adapted to eat the right size of seeds, and so on. But a neuroscientist, when they talk about adaptation, is talking about a plastic response of the body to accommodate the environment. There’s tons of that that occurs in Harvard students. I mean, it’s an extraordinary social experiment we run every year, putting a bunch of valedictorians together. That’s an enormous amount of social stress and friction, but the human mentality is such that it quickly adapts appropriately. We have all these brilliant people who could rub each other [wrong] — and sometimes do of course — but more often really pull together for the common good.

FM: You deliver the annual Bulldog Roast for Harvard-Yale, but if you could roast Harvard instead, what would you say?
AJB: It would be a four-hour roast just talking about my.harvard, which is the single worst piece of IT infrastructure in existence. It’s extraordinary that a major academic institution should be brought to its knees at the beginning of every semester because my.harvard doesn’t work. But the sad news is, we can make jokes about Harvard and roast it, but it’s never going to be as easy as roasting Yale, which is woefully inadequate on so many fronts.

— Associate Magazine Editor Saima S. Iqbal can be reached at saima.iqbal@thecrimson.com. Follow her on Twitter @siqbal839.