Science Magazine Podcast
Transcript, 20 July 2012
http://podcasts.aaas.org/science_podcast/SciencePodcast_120720.mp3
Music
Host – Isabelle Boni
Welcome to the Science Podcast for July 20th, 2012. I’m Isabelle Boni.
Host – Kerry Klein
And I’m Kerry Klein. This week: the evolution of sex chromosomes in fruit flies [00:56],
the painstaking process of watching climate change in action [11:00], and some career
advice:
Interviewee – David Jensen
In the scientific world, when you talk to scientists about their experiences, they always
use the term “we”—that is a detractor when you’re out in the job market [20:39].
Host – Isabelle Boni
Plus, a few stories from our online daily news site.
Promo
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Advancement of Science. Advancing Science, Engineering, and Innovation throughout
the World for the Benefit of All People. AAAS—the Science Society—at www.aaas.org.
Music ends
[00:56]
Host – Isabelle Boni
A new paper in Science uses a study of Drosophila miranda, a fruit fly species, to shed
light on the complex question of how natural selection shapes sex chromosomes. The
interactions between X chromosomes, Y chromosomes, and autosomes—and their
respective quirks— all factor into the evolution and development of so-called neo-sex
chromosomes in these flies. I spoke with co-author Doris Bachtrog from the University of
California, Berkeley, about the research.
Interviewee – Doris Bachtrog
We are very interested in understanding the evolution of sex chromosomes. Sex
chromosomes – which are X and Y chromosomes – originated from ordinary autosomes,
but all sex chromosomes are very different from each other. The Xs were different from
the Y chromosomes, and they are also very different from autosomes. So X
chromosomes typically contain many hundred or many thousand genes, but Y
chromosomes only have a few genes. And so we are interested in understanding the
molecular forces and the evolutionary processes which create and shape X chromosomes.
Interviewer – Isabelle Boni
Now to backtrack a little bit, how does a sex chromosome differ from other
chromosomes?
Interviewee – Doris Bachtrog
In humans, for example, each human has 23 pairs of chromosomes. And 22 of those
pairs are completely identical between males and females, and those chromosomes are
called autosomes. The last pair – and that’s the sex chromosomes – you actually have a
sex-determining function of this chromosome. And in humans – and the same is true for
fruit flies – you have two X chromosomes in females, but you have an X and a Y
chromosome in males. So that’s the main difference between sex chromosomes is that
they are inherited differently between sexes, and they contain sex-determining functions.
Interviewer – Isabelle Boni
How about a little bit of discussion on how X and Y chromosomes differ from each other.
Interviewee – Doris Bachtrog
I think there are three main differences from an evolutionary perspective of how X and Y
chromosomes differ from each other. So the first one is that X chromosomes and Y
chromosomes, they don’t undergo meiotic recombination. For each autosome, you have
a copy from mom and one from dad, and during meiosis they exchange genetic material,
so they undergo what’s known as genetic recombination. And the X and the Y
chromosome are not undergoing meiotic recombination. The second difference is that
the sex chromosomes show sex bias transmission. The Y chromosome is only
transmitted through males, X chromosomes are more often transmitted through females,
and so you have sex-specific selection operating differently on sex chromosomes
compared to autosomes, and they operate differently on the X versus the Y chromosome.
And so the last difference is that each autosome, again, is – you have a copy from mom
and one from dad. But for sex chromosomes, for the X chromosome, females have two
copies, but males only have a single copy. So males are hemizygous for the X
chromosome. And so recessive selection operates very differently on the X chromosome
compared to autosome in males. So because of these very unique patterns of how sex
chromosomes are inherited compared to autosomes, there are very different evolutionary
predictions of how you would think selection would operate on sex chromosomes. So the
first main difference between the X and the Y chromosome is that there’s a lack of
recombination on the Y chromosome. And because of this lack of recombination, natural
selection is much less efficient operating on the Y chromosome. Then it goes back to this
entire, like, bulk of literature of why recombination and why sex evolved in the first
place, and the general idea that you need recombination in order to allow selection to
operate efficiently. And on Y chromosomes, you don’t have recombination, and
therefore selection isn’t efficient. And in the long term, because of this lack of selection
being efficient, you actually lose most of the genes from the Y chromosome. In our study
system in this Drosophila miranda species which we are looking at, we can actually see
this ongoing massive gene decay on the Y chromosome.
Interviewer – Isabelle Boni
So could you please elaborate on how recombination is related to efficient selection?
Interviewee – Doris Bachtrog
So that’s this general idea that if you have multiple mutations segregating on a
chromosome, if you have recombination then selection can operate on each mutation
individually. So you could imagine if you have a chromosome where you have a
beneficial mutation occur – one that’s one that’s good for the organism – and on the same
chromosome, you also have some detrimental mutations, and they just happen to be on
the same chromosome. So if you have recombination, then you can easily just recombine
this beneficial mutation away from its detrimental background, and this beneficial
mutation can become established in the population without dragging along nonfunctional
mutations or deleterious mutations. But if you have the same occurring on a nonrecombining chromosome – and a Y chromosome, if you have a beneficial mutation
that’s one block within the genome, and there’s this beneficial mutation, this link to
deleterious alleles on the same chromosome, if you fix this beneficial mutation, it will
drag along deleterious mutations that are linked on the same chromosomes. So you have
this what’s known as genetic hitchhiking. You fix the beneficial mutation, but you do it
at the cost of fixing links to deleterious mutations. And that’s the type of flavor of
models that can explain why selection is not efficient on a non-recombining
chromosome, and why you might degenerate linked genes on a Y chromosome.
Interviewer – Isabelle Boni
So now we’re going to move on to some difficulties in your research. It seemed from
reading your paper that it was quite difficult to figure out the relative ages of
chromosomes. How do you address this sort of obstacle?
Interviewee – Doris Bachtrog
In humans, it’s much harder to figure out the age of the sex chromosomes, because the
sex chromosomes in humans are very, very old. They are several hundred millions of
years old, and so you have lost most of the homology between the X and the Y
chromosomes. So it’s much harder to identify how old they are. But in our species, the
Drosophila neo-sex chromosomes that we are using – the sex chromosomes – they have
formed very recently, so there’s actually a lot of homology between the X and the Y
chromosome still remaining. And so we can just look at how much difference there is
between X and Y chromosome in order to infer how old the chromosome is. So the older
the sex chromosome is, the more differences have accumulated between homologous
regions.
Interviewer – Isabelle Boni
Alright. Are there any other key results you would like to talk about?
Interviewee – Doris Bachtrog
We also find that while the vast majority of genes are degenerating on the Y
chromosome, there’s a substantial fraction, there’s several hundred genes which are
undergoing male-specific selection. So there’s a selection for male improved function at
a large fraction of genes. And we refer to that as masculinization since there are many
genes which are only transmitted through males, and then they’ll start to evolve specific
expression patterns of only being expressed in testes, or essential increased protein
evolution to perform male-specific functions. So there is this pattern of mass
degeneration, but also ongoing masculinization of the remaining genes that survive on the
Y chromosome. And the whole other part of this study was actually looking at the X
chromosome as well. On this aspect, we also had some surprising results. So I
mentioned before that the X chromosome is more often transmitted through females, so
one would expect the X chromosome to harbor female-beneficial genes. And that’s
what’s generally being seen at old sex chromosome. At old X chromosomes, there’s an
excess of female-beneficial genes. And so in the very young X chromosome, we also see
evidence for masculinization of the gene content. So there’s this conflicting selective
pressures in X chromosomes. On one hand, selection is more efficient on recessive male
beneficial mutation, so it might become masculinized. But on the other hand, it’s more
often transmitted through females, and therefore it might become feminized. And so
there is this opposing selection. And we see both types of selection, depending on
whether we look at the old ancestral sex chromosomes, or whether we look at the young,
recently formed sex chromosomes.
Interviewer – Isabelle Boni
So what are some future directions you would like to take your research?
Interviewee – Doris Bachtrog
In this current paper, we report the neo-sex chromosomes of one specific species of
Drosophila miranda where we look at sex chromosomes which are one million years old.
It’s a nice example of a chromosome that’s pretty much halfway through becoming a
heteromorphic sex chromosome. So it has a lot of its signatures of its autosomal origin,
but it also has a lot of signatures of being a heteromorphic sex chromosome. But a big
benefit in Drosophila is that we have a whole variety of species which have neo-sex
chromosomes of different ages, so we can look at much younger neo-sex chromosomes
which have many more autosomal characteristics. And so we are doing similar genomic
and transcriptome approaches in different Drosophila species to look at different ages of
sex chromosomes. We are also getting much more interested in what’s going to happen
on a more molecular and mechanistic levels of which exact changes are causing this
degeneration, and the down-regulation. And we are also looking at the X chromosome in
more detail of how it is responding to Y degeneration, and in particular the X
chromosome is starting to evolve through this compensation, so we are looking at
evolution of dosage compensation. And then final angle, we are starting to take this
research of looking at what’s going to happen at old ancestral sex chromosomes. So are
highly diverse sex chromosomes really just evolutionary traps, like as they’re often
viewed in mammals? That once you have highly heteromorphic sex chromosomes, can
you ever evolve back into having autosomal inheritance? Or is there actually an option
of them becoming autosomal again? So we’re looking at transitions of sex chromosomes.
Interviewer – Isabelle Boni
Thank you, Doris Bachtrog.
Interviewee – Doris Bachtrog
Okay, thank you very much.
Host – Isabelle Boni
Doris Bachtrog and Qi Zhou report on the evolution of sex chromosomes in a Report in
this week’s Science.
Music
[11:00]
Host – Kerry Klein
When the weather gets hot, most of us can’t resist jumping into the ocean or holing
ourselves up in air-conditioned spaces. But nature doesn’t have it so easy: a drastic
change in prevailing temperatures could lead to drastic changes to a whole ecosystem.
Predicting the magnitude of these changes can be tricky, but a decade-long research
project in South America aims for a real-time look at the effects of climate change on
trees. Jean Friedman-Rudovsky spoke to me about this unique initiative from La Paz,
Bolivia.
Interviewee – Jean Friedman-Rudovsky
Every plant species, when a climate changes around it, has three options, essentially. It
can either move – it can move to a place where there are more ideal climatic conditions,
more rainfall or less rainfall, depending on what it needs; it can adapt where it is and try
to survive in the environment, even though the environment is changing around it; or the
tree can die off. So essentially this project is about scientists collecting information to try
to predict which species might do which in the future.
Interviewer – Kerry Klein
And this whole story takes place in Madidi National Park in Bolivia. So first, just tell me
about this park – what kind of environment is there, what kind of species live there, what
makes it such a special place?
Interviewee – Jean Friedman-Rudovsky
Madidi National Park is actually one of the largest, most biodiverse protected areas in the
world. It’s in northwestern Bolivia. It’s about the size of Vermont. There are over
12,000 plant species in the park. And 11% of the world’s bird species can be found in
Madidi, as well. But what really makes it unique, particularly to this sort of biodiversity
research, is the fact that it has the longest elevation gradient on the planet, meaning there
are parts of the park that top out over 6,000 meters – Andean peaks – and it goes down to
almost sea level. And so what you have is just a tremendous range of different
environments and different climates all contained within one protected area that has very
little human activity around it.
Interviewer – Kerry Klein
So this is really quite a unique place. So all of this research that you’re talking about
takes place within the context of something called The Madidi Project. So how exactly
does this work? What data are scientists collecting? And how are they hoping to
determine how trees are responding to climate change?
Interviewee – Jean Friedman-Rudovsky
The Madidi Project is actually a program of the botanical garden out of Missouri in the
United States, and it coordinates research with researchers and scientists here in Bolivia.
They have about 500 plots that they’ve established over the last 10 years. And these
plots sort of range in size between a tenth of a hectare to one hectare large. And what
they do is, in each of these plots, they’ve put little tags on every mature tree – meaning
every tree that has a diameter of over 10 cm. And they try to come back every few years
– ideally every 5-6 years – they try to come back and look at the changes in these trees.
They look at their growth rate, they look at maybe whether any of the trees have died,
whether there are new trees. They examine every single characteristic. And so what
they’re trying to do is collect an extraordinary amount of data that will help them
understand how these trees are reacting to the fact that the climate is changing around
them.
Interviewer – Kerry Klein
And how long have these studies been going on?
Interviewee – Jean Friedman-Rudovsky
These studies have been going on for over a decade now. They hope to go on much,
much longer. It’s very difficult to do this kind of work. It’s very meticulous work. It’s
hard work. There’s often not a lot of funding that will sustain a project for more than this
amount of time, so that’s why this is one of actually the longest projects of this type.
Interviewer – Kerry Klein
So as you said earlier, this project was spearheaded by a group of scientists at a botanical
garden in Missouri in the United States. So to what extent are they collaborating with
researchers on the ground there in Bolivia?
Interviewee – Jean Friedman-Rudovsky
They work directly with the various botanists and biologists out of Bolivia’s largest
public university, the Higher University of San Andrés, here in the capital of La Paz.
And this coordination is extremely important. It’s mainly the Bolivian scientists that are
doing a lot of this research on the ground. For example, the trip that we took in April, we
had one scientist who came from the United States, Peter Jørgensen, but the rest of the
group were Bolivians. And it’s a very big and important part of this project that they’re
trying to not only work with Bolivians here, but really empower them to be able to do a
lot of this research on their own, and to improve some of the scientific skills that are in
this country.
Interviewer – Kerry Klein
So let’s step back for one second. Can you just tell me what a day in the life is like for
these researchers in this really amazing forest?
Interviewee – Jean Friedman-Rudovsky
It is certainly not easy. I mean, it took us five days just to – from La Paz – get to the site
where the campground was going to be, and to start actually doing the measurements and
data collection that they would be doing over the next three weeks. Everything you can
assume about, you know, camping – bathing in the river, having to bring all of the food
and every single supply in with you possible. And, on top of that, the complications of
being in a natural environment, whether there stinging ants or a bee infestation in the
campground…
Interviewer – Kerry Klein
Having to boil your water…
Interviewee – Jean Friedman-Rudovsky
…exactly. Having to boil your water. It rains at night and the tents get flooded. You
know, there’s a million and one things that can come up on an expedition like this. So
it’s not easy work at all to be out there for so long. And the days are long, and as I said,
it’s very meticulous work. They are checking every single characteristic of these trees,
whether it’s the smell, the bark texture, the height, the pattern of the leaves, everything to
make sure, first, that they understand and have identified the species of the tree correctly,
and then to be able to accurately measure how it’s changing over the years.
Interviewer – Kerry Klein
Right. Well, this all kind of sounds like an adventure to me, but I suppose after a few
days it might not be so fun any more. Now coming back. As you said earlier, faced with
a changing climate, trees basically have three options. They can adapt in place, they can
move, or they die off. So now that this study has been going on for over a decade, what
have scientists observed about how these trees are adapting to climate change?
Interviewee – Jean Friedman-Rudovsky
Right. Well, they’re hesitant to make too many, you know, sort of certain conclusions.
But essentially what they are seeing is that for many of these trees, it’s easier for them to
move – to short of shift uphill, for example, to escape rising temperatures – than for them
to adapt where they are. Now that doesn’t necessarily mean that every single tree is able
to do this. For example, if there’s a tree that has a very large what’s called a buttress –
sort of very large root structure at the bottom – if it’s moving up a mountain, areas with
higher altitude are more likely to be on a sloped surface than to be flat. And so it may be
that some of these trees that can survive very well at say, 500 meters in altitude, if it’s
attempting to flee rising temperatures and it’s moving up a slope, it may not be able to
survive at a higher altitude, because it’s more likely that the ground there is inclined. So
it really changes, depending on every individual tree, but in general they’re seeing that
it’s easier for them to move than to adapt.
Interviewer – Kerry Klein
So this brings in the concept of range shifts in which, you know, a species can move to
where its preferable climate zone is moving. This is relatively easy to understand for
animals that are mobile and, you know, have legs and can move. But what exactly does
this mean for a tree? Is the tree itself moving?
Interviewee – Jean Friedman-Rudovsky
No, it’s not exactly that the tree itself is moving, but it has various sorts of regeneration
mechanisms. So through seed dispersal and some of these other mechanisms, it’s
actually trying to help its next generation move to a different space. Exactly. It’s not that
the tree itself is moving, but that its next generations would be in a different place.
Interviewer – Kerry Klein
So what can we learn from all of this? Now that we suspect that these trees in this
particular forest are moving as a response to their changing climate, what are the next
steps to take with this knowledge in hand?
Interviewee – Jean Friedman-Rudovsky
Well, I think the real goal of this study is to be able to create a better conservation policy
in the future. You know, there’s limited money for conservation. We’re not going to be
able to try to protect every single natural environment that exists in our world. So what
these researchers are trying to do is figure out, okay, if there are some trees that really are
less likely to adapt, are less likely to move, they won’t necessarily be able to survive.
And then maybe what we should be doing is putting our attention and putting our funding
into conserving the environments where these species do exist now. So it’s really about
trying to take this scientific knowledge and give it some real-world function. And the
Missouri Botanical Garden is hoping to be able to find more funding. Again, since this is
one of the most unique projects of this type – and one of the few projects of this type –
they’re hoping to be able to get more funding. Because, as these scientists say, even
though they’ve been studying this for a decade, that’s still not enough time to really
understand how these trees are going to react in the future.
Interviewer – Kerry Klein
Indeed. Well, Jean Friedman-Rudovsky, thank you so much.
Interviewee – Jean Friedman-Rudovsky
Thank you, Kerry.
Host – Kerry Klein
Jean Friedman-Rudovsky writes about the trees of Madidi National Park in a News Focus
this week.
Music
[11:39]
Host – Isabelle Boni
Beginning a career as a young scientist isn’t easy, whether you're in a lab, at a small
startup company, or just hitting the job market. David Jensen, a regular contributor to
Science Careers, has some advice for young career-starters in his column this week. A
self-described “headhunter,” he meets with a lot of CEOs and other occupants of the
luxurious corner office, or C-suite—and he knows a thing or two about what they want
from their employees. Donisha Adams of Science Careers spoke with Jensen, who began
by explaining how he came across all these tips and tricks.
Interviewee – David Jensen
My work life is really comprised of lots of daily interviews. Twenty-some years ago, I
started saying what do I do with this stuff? I’ve got all this collected advice, all these
collected experiences from other people. And I really continue, at this point in time,
every month now, turning these stories into columns about career topics. And this has
been more than 15 years on a regular monthly basis.
Interviewer – Donisha Adams
Can you tell me what is your Science Careers column about this month?
Interviewee – David Jensen
My column’s called Tooling Up. And my current story is called “Advice From the CSuite.” And it’s chock-full of what I call O.P.E.
Interviewer – Donisha Adams
Well, what does O.P.E. stand for?
Interviewee – David Jensen
This O.P.E. – other people’s experience – is what drives processes, like networking or
informational interviewing – a whole lot of things that I talk about regularly on Tooling
Up. It’s just interesting that this stuff I bring in my columns, this other people’s
experience, because after 10,000 interviews, I’ve learned a lot about what scientists,
technical professionals, business people, engineers – I learned a lot about what they do
right and what they do wrong.
Interviewer – Donisha Adams
Dave, you mention networking, and that reminds me that in a number of your articles,
you refer to something you call peer+2 networking. Well, what exactly does that mean,
and how does that tie in with your O.P.E.?
Interviewee – David Jensen
This peer+2 framework that we talk about for networking, we do a lot of discussion about
this in the Science Careers forum, as well, which is an interesting moderated discussion
panel that goes on all the time on the Science website. But you’ll hear people say get out
there and network, you really need to find people who are just a year or two ahead of you.
That’s the “peer+2” element. And you ask them how they did it. Really amazing fact of
life, but as soon as you turn the focus off of you, your job search, your job mates, people
start to talk. And that’s the point. You listen. You gather those experiences. And
networking is really enriched by that whole process. The reason that I talk about that in
this column this month is that my company president, Greg Duerksen, works with people
at this level all the time. And the O.P.E. that this guy gathers is unique. And this month I
passed along this advice from our corner office, so to speak. Greg refers to these topics
as “The New Standard” because he says that he’s certain that not only is this important
advice, but it’s absolutely the new standard by which people hire. In other words, the bar
has been raised substantially over the last few years about how it is we make hiring
decisions in companies like these.
Interviewer – Donisha Adams
You mention your company president, Greg Duerksen, in your article. He says that good
senior executives need to be able to think strategically. Well, what does this strategic
thinking mean for an early career scientist?
Interviewee – David Jensen
Well, he not only mentions strategic thinking, he mentions tactical abilities at the same
time. It’s really important for even the early career professional to think both
strategically and tactically. And what I mean by that is let’s say, for example, that you’re
a scientist hired right out of a post-doc to do a particular assay, because you’re good in
this particular area of cell-based assays, for example, and you’re hired to do that. Well,
who do you think is going to get a promotion? The person who thinks only of that assay
in front of him or her at the bench, or the person who sees that assay as one piece of a
great big puzzle of work that has to be done to get a drug approved and into the market?
It’s that latter person that’s going to get promoted. When you can see the whole picture
of how it is that your work fits into the company’s goals, that’s what senior executives
are looking for in their scientists.
Interviewer – Donisha Adams
Another thing that Duerksen says is that you need to engage in the gray and drive it into
black and white. Well, what does he mean by that?
Interviewee – David Jensen
Let’s say you’re a CEO and you’re looking for funding for your young company.
Finding funding could look like a gigantic gray cloud above you. Where does it come
from? You’ve got to drive forward into that gray. You can’t be afraid. You have to
identify the process by which you’re going to get something done. You go out there and
you do it.
Interviewer – Donisha Adams
Well how does that apply to less experienced employees?
Interviewee – David Jensen
I have a general manager that recently came to us and said they need to hire a research
scientist. Now this was a contract research organization that provides services to
companies. And they weren’t necessarily in trouble, but their business really wasn’t
growing. So the general manager hired a person who he thought could really work in the
gray zone – in other words, who could work in the uncertainty of what exactly it is that
companies need for these services. And he gave that person the freedom to go out and
find new services that they could offer to drug company clients. And this young scientist
actually went out, sat in the offices of colleagues and companies that were doing business
with them, and asked them what do you need? You know, what are the services that you
don’t have available from providers like us? And he found a whole series of new
services that he helped this company integrate into their business plan. And so that’s how
one young person happened to make the change by embracing this gray area, driving it to
black and white, and getting things done. It’s a focus on results that managers are
looking for when they make a hiring decision now.
Interviewer – Donisha Adams
Duerksen recommends maintaining a 1:1 ego-to-capability ratio. What does he – and
what do you – mean by that?
Interviewee – David Jensen
Yeah, 1:1 ego-to-capability ratio. That’s because sometimes we see people who are
either cranking up their ego way too high, or someone who, in the scientific world, is way
too low. For example, you know, in the scientific world, when you talk to scientists
about their experiences, they always use the term “we” so often. “Well, we in the Smith
Lab do this kind of work,” or, “we have published this,” or, “we have published that.”
That is a detractor when you’re out in the job market. When you’re in a job market,
you’re expected to be able to talk confidently about what you do and what you do well.
So getting to a 1:1 ego-to-capability ratio means that you understand the whole topic of,
for example, self-promotion. Self-promotion sounds ugly on the surface. It’s something
you think of when you hear of a used car salesman, or, you know, the really unethical
self-promoter who looks like they have a wildly out of whack ego-to-capability ratio.
Someone who just seems quite egoistical. But you need to be able to state what it is you
do and what you do well. For example, I saw a workshop. This great speaker, behavioral
scientist, George Dudley, described what he calls the fear of self-promotion, and I’ll give
that to you here. Here’s his description: “The fear of self-promotion consists of all
behavioral habits, thoughts, actions, or feelings that conspire to keep competent people of
all walks of life from being able to stand up and take credit for who they are and what
they do well.”
Interviewer – Donisha Adams
Well, another term that you mention is “strategic doer.” Can you tell me what does being
a strategic doer mean?
Interviewee – David Jensen
This is a white paper that Greg wrote. As a part of “The New Standard,” he said, “Be a
strategic doer, but also be able to simultaneously lead others.” And that’s a difficult thing
to do. When you’re a young scientist, for example, or a young engineer, you’re brought
onboard a company to do a job. It’s very difficult, because you’re given all kinds of
priorities. And a strategic doer takes a look at this list of 20 things that have to be done
today, and knows exactly which ones you can do, and which ones you need to count on
others to help you with. And that’s where most employees fail. It’s understanding that
others are out there, and they’re able to help you. It’s job number one when you’re
learning to do your work in a company is to learn to delegate. Or if you don’t have
people working for you, as many people won’t, you have to learn something even tougher
than that, and that’s called influence without authority. And that’s something that you
can learn as an early career scientist. It’s something that will provide the background that
you need to help you learn to delegate when you are a manager. And when supervising
others, you’ll need that experience. So it’s something that can come to you in the first
couple of years of your work experience. Becoming a strategic doer can really improve
your career options, as well.
Interviewer – Donisha Adams
Dave Jensen, thank you for this interview.
Interviewee – David Jensen
Thank you, Donisha.
Host – Isabelle Boni
David Jensen is a regular contributor to Science Careers. His latest column, “Advice
From the C-Suite,” can be found at sciencecareers.sciencemag.org.
Music
[29:57]
Interviewer – Edward Hurme
Finally today, I’m here with online news editor, David Grimm, who’s here to give us a
rundown of some of the recent stories from our daily news site, news.sciencemag.org. So
first up we have an article about punishing cheaters. When it comes to fairness, do we
act like Batman?
Interviewee – David Grimm
Well that’s the question we sort of ask. And the reason we sort of invoke Batman is
because there’s been a controversy in this whole field of cheating. And this is actually
something that scientists study. They’re trying to figure out when somebody cheats us –
say somebody picks your pocket in a subway and you punish them, you want to see them
punished – do you want to see them punished because you don’t think it’s fair that they
took your money? Or do you want to just see them punished because you’re seeking
revenge? And I know those two might sound kind of similar, but there’s actually a
difference between seeking revenge and actually just trying to what scientists call avoid
inequity aversion. That is, are we just seeking revenge, or are we trying to mainly just
sort of make sure the scales are sort of even? And that’s been a really hard thing to tease
out. And this new study tries to do that.
Interviewer – Edward Hurme
So what was the setup for the experiment?
Interviewee – David Grimm
So what they tried to do in this new study was they recruited about 500 people on the
internet, and they had them play this very simple economic game where they divided
everybody into teams of two people. And one person was the cheater, and one person
was the cheated. There were basically three scenarios. In the first scenario, the cheating
partner started out with significantly less money than the cheatee. And the cheating
partner could choose to steal 20 cents, but this didn’t increase his fortunes enough to
equal the fortunes of his partner. In the second scenario, the money was distributed so
that if the cheating partner stole 20 cents, basically him and his partner now had the same
amount of money. And finally in the third scenario, if the cheating partner stole 20 cents,
he actually ended up with more money than the person that he cheated from. And then
what the researchers did is they allowed the partner that had been cheated to pay 10 cents
– they could use 10 cents of their money – to punish the cheaters for their actions. And
what they found in the first two scenarios where the cheater had either not taken enough
money to equal the other partner’s fortune, or taken just enough money to equal the other
partner’s fortune, there was about the same amount of punishment going on. But in that
third scenario where the thief basically took so much money that he actually had more
money than the person he stole from, the rate of punishment doubled. And what this
suggests to the researchers is that it’s our sense of fairness. We really feel like that’s
unfair. If someone steals money from us, it’s that sense of unfairness that really
motivates us to punish them – not just, hey, they stole some money, they should be
punished, but they’re stealing money and it’s making things unfair. When they do that,
we want to sort of set things right again.
Interviewer – Edward Hurme
Maybe kind of like Bernie Madoff is the example of this tycoon who took everyone’s
money.
Interviewee – David Grimm
Exactly.
Interviewer – Edward Hurme
And everyone was very furious about this.
Interviewee – David Grimm
Exactly. And the question is do we want to punish Bernie Madoff just because he took
money? Or do we want to punish him because he took so much money and enriched
himself so much while making other people potentially very poor? And this study
suggests it’s really the latter. What he did created such a vast gulf of unfairness that
that’s really what we’re trying to punish.
Interviewer – Edward Hurme
So from our superhero sense of fairness to what’s fair in the rodent world, you have
another story about rodents robbing each other in the rainforest.
Interviewee – David Grimm
Right. This is another story about robbing. This robbing though, seems to have had
positive consequences. This story deals with a plant called the black palm tree, which
lives in Panama. And this tree has these really big seeds. They’re about the size of a
cherry, and they’re located in this fleshy fruit at the top of the plant. And the seeds are in
such a place – I mean, they’re really high up on the plant and they’re really big – that you
would think, well maybe only a really big animal should be able to get up there, grab the
seeds, and, for lack of a better word, poop them out somewhere else, so that would cause
new black palm trees to be seeded in other places. The problem is that that scenario
actually used to exist. About 10,000 years ago, there was an elephant-like creature called
a gomphothere, which lived in the same place that these trees do, which is in Panama. It
was big enough to be able to grab that fruit and eat it, and poop those seeds out all over
the place. And that was great for the plant. The problem is these gomphotheres went
extinct about 10,000 years ago, and the plants are still around. So the question is how are
these plants still around if the animal that’s supposed to be helping them survive has been
gone for thousands and thousands of years?
Interviewer – Edward Hurme
So there was an empty niche open.
Interviewee – David Grimm
Exactly. And that’s where the rodents come in. This is a cat-sized rodent called the
agouti. And researchers already knew that the agouti played some sort of role with the
seeds of this black palm tree. They had observed the agouti take these seeds, they bury
them in a certain place, and they sort of use them as a backup food source. So if food
runs out, they go back to where they buried the seeds and eat them. Well that’s not really
great for the trees, because if the seeds get eaten, the rodents actually tend to eat the seeds
in such a way that they destroy them. So it’s not like they can poop them out and create
new plants like the gomphotheres did. But they also noticed that the rodents didn’t
always go back and eat the seeds. Sometimes they would just transport them to a
location, forget about them, and, theoretically, that would grow into a new plant. But the
question was were the agouti really transporting these seeds far enough and wide enough
that it really would have a positive impact on the population of these black palm trees?
And that’s sort of where the new study comes in.
Interviewer – Edward Hurme
So how did they test the movement of these seeds?
Interviewee – David Grimm
What they did was they actually attached radio trackers to 589 of these seeds. And they
placed the seeds at 52 different sites on Panama’s Barro Colorado Island. And what was
funny is right away the agoutis sort of ran to these piles of seeds, they took them, and
they started hiding them. And the researchers were able to track these seeds over about
the course of a year – and you can actually see a video on the site of these seeds sort of
moving from place to place over a year, it’s pretty cool. And what they found is that the
agouti were really transporting these seeds really far away, sometimes as far away as 280
meters. Sometimes they were moving the seeds more than once a day. So they were
moving these seeds all over the place. And sometimes they were eating them, but
sometimes they were just forgetting about them. And their conclusion from all this is that
the agouti really are transporting these seeds far enough and wide enough that it appears
that they’ve really kept this black palm tree going for thousands of years, even though the
creature that it relied on – the gomphothere – has been extinct for a long time.
Interviewer – Edward Hurme
And finally, from rodents helping ecosystems, our next story is on algae cooling the
planet.
Interviewee – David Grimm
Well, Edward, this story has to do with the question of whether algae that live in the
ocean actually play a major role in the climate on Earth. And there’s been a hypothesis
called the Iron Hypothesis that’s been going around for a while now, which suggests that
dust blown from land that’s very rich in iron lands in the ocean. Algae eat this dust, and
they like the iron. And as they’re eating the iron, they grow bigger and bigger and
bigger. And these algae are photosynthesizing, and to photosynthesize, they’re actually
sucking up carbon from the atmosphere. So they suck up all this carbon, they grow
bigger and bigger, they suck up more and more carbon. And then they die, and they sink
to the bottom of the ocean. And the reason that can cause climate change is because CO2
is a greenhouse gas. So if you’re sucking a lot of it out of the atmosphere, you’re
potentially cooling the planet. And scientists had suggested that potentially some of the
effect may have been so dramatic that some of the past ice ages on Earth may have been
caused simply by dust falling onto the ocean, and you have these huge what are called
algal blooms forming, and that could have sucked enough CO2 from the atmosphere to
really lower Earth’s temperatures. But nobody has been able to show this. And
obviously it’s a hard thing to prove, because how are you going to recreate this in the real
world?
Interviewer – Edward Hurme
Yes, so how did the researchers go about testing this hypothesis in the open ocean?
Interviewee – David Grimm
Yes, and actually the researchers actually did go out and test this in the real world. They
went to the Southern Ocean. And what they did that was really neat is they looked for
what are called eddies, which are these basically big whirlpools in the ocean. The reason
that they wanted to look for these is because they wanted to add a lot of iron to the water,
but they wanted to find a way to mix it. I mean, you can’t just sort of stir, you know, get
an oar out and stir a bunch of iron into the water. So they actually looked for these
whirlpools where it’s sort of these natural spinning beakers in the water. And they found
one. They dumped a bunch of iron – actually 14 tons of iron sulfate – into the seawater.
And then they monitored algae growth over the course of several weeks. And what they
found was they were able to actually create this huge algal bloom, which swelled to over
800 square kilometers. And they were able to observe this via satellite. And what they
did is once this bloom formed, they sort of – you know, this is a very rough, rough patch
of ocean – they would drive their boat in there every few days, take some samples, and
see what was happening with the algae. And first of all, obviously the algae were really
growing a lot, which suggests that the iron really does play a big role in their growth. But
what they also found is that over the course of a few weeks, at least half of the total
biomass of all of this algae sank to a depth of below a thousand meters in the ocean,
which means that if these guys really were sucking up carbon dioxide from the air –
which they probably were, because they had to to grow that much – they were not only
sucking it up, but they were basically sequestering it down in the bottom of the ocean and
taking it out of the atmosphere. And theoretically, if this was happening on a very large
scale, it could actually have a significant impact on global temperatures.
Interviewer – Edward Hurme
So geoengineering is still kind of a touchy subject. Is this a potential approach for
dealing with climate change?
Interviewee – David Grimm
Right. So geoengineering – this is this whole idea that, you know, the Earth is warming,
is there something man-made that we can do to sort of combat global warming, reverse it,
or even if we can’t reverse it, maybe ameliorate it a bit? And one of the ideas has
actually been throwing a bunch of iron into the ocean, creating these huge algal blooms,
and seeing if we can maybe not create another Ice Age, but at least cool the world enough
that it would lower global temperatures a bit. But, as you suggested, this is very
controversial, this whole idea of sort of mucking with nature. People really don’t know
what the side effects would be of creating these huge algal blooms. Yes, it might cool the
air a bit, but it could have other consequences as well. So researchers are saying just
based on this one study, we really shouldn’t go ahead with this until we know a whole lot
more about how this process works.
Interviewer – Edward Hurme
And what else have we had on the site this week?
Interviewee – David Grimm
Well, for ScienceNOW, we’ve got a story about the farthest spiral galaxy ever
discovered. Also, a story about how mosses use scent to attract pollinators. For
ScienceInsider, our policy blog, we’ve got a story about new figures on the global AIDS
epidemic. Also, a story about what the future holds for funding at the National Institutes
of Health. And, finally, for ScienceLive, this week’s ScienceLive is about science and
the Olympics – how is science both leveling and unleveling the playing field? So be sure
to check out all of these stories on the site.
Interviewer – Edward Hurme
Thanks, David. David Grimm is the online news editor for Science. You can check out
all our news at news.sciencemag.org, including daily stories from ScienceNOW, and
science policy from ScienceInsider. While you’re there, be sure to check out
ScienceLive, a live chat on the hottest science topics, every Thursday at 3 p.m. U.S.
Eastern time.
Music
Host – Isabelle Boni
And that concludes the July 20th, 2012, edition of the Science Podcast.
Host – Kerry Klein
If you have any comments or suggestions for the show, please write us at
[email protected].
Host – Isabelle Boni
The show is a production of Science Magazine. Jeffrey Cook composed the music. I'm
Isabelle Boni.
Host – Kerry Klein
And I’m Kerry Klein. On behalf of Science Magazine and its publisher, AAAS, thanks
for joining us.
Music ends