Animal Models vSITN

Written by Michelle Frank, Alexandra Schnell, Mashaal Sohail, and Amy Gilson

Part One (Listen to Part Two here)

Rebecca Hi Amy

Amy Hi Becky. Or, do you want me to call you Rebecca for this podcast?

Rebecca Probably Rebecca.

Amy Okay, Hi Rebecca

Rebecca Hello Amy!

Amy Can you explain who you are and why you’re here?

Rebecca I’m a graduate student at Washington University, St. Louis and I’m also your sister. I guess I’m here because I’ve been vegetarian for ages, but decided to do research where I’d have to use mice.

Amy When did you become vegetarian?

Rebecca When I was eight, you were there, don’t you remember?

Amy Haha, of course I do, but indulge me.

Rebecca Right, so one night we were eating dinner

Amy Chicken dinner

Rebecca and I asked, “Why can’t we breath underwater?”

Amy You want to just role play this? I’ll be the parents, and you can be yourself but… eight.

Rebecca Haha, sure. So you’re “Dad” now?

Amy Yup! [Low voice] There’s a lot of oxygen mixed in with the air we breathe, but in water, there’s not enough oxygen mixed in for us to survive breathing in it. However, there are special liquids with extra oxygen in them. People have done experiments where they put mice in these liquids and the mice could survive breathing in them, at least for a while.

Rebecca Wow, that’s so cool. So what happens to the mice once they get out of the liquid?

Amy They die.

Rebecca Why should people do that if it kills the mice? It’s not nice.

Amy [As Mom] You don’t think it’s okay to use mice here? What about to make new medicines? New medicines get tested on mice and other animals all the time. And then these medicines can save a lot of people’s lives. Do you think that’s ok?

Rebecca I’m not sure.

Amy [As Mom] But if you don’t think it’s ok to sacrifice animals to save people’s lives, then why do you eat meat? You’re sacrificing an animal, but you don’t necessarily need it to live or be healthy.

Rebecca Okay, well, I guess I’ll stop eating it then.

Amy [As Mom] Okay, but you have to at least finish what’s on your plate.

Rebecca And that was that!

Amy It really was! At the time, I thought it would last a week, but in the end, you dragged the whole family down with you.

Rebecca Well that puts a positive spin on things.

Amy But 14 years later and you’re sacrificing mice yourself as part of your PhD research. You could have chosen research that didn’t involve animals at all. Or that studied bacteria or yeast.

Rebecca Sure, but the whole thing was that I wanted to do work that would be likely to benefit people’s health directly, and a lot of times that research just needs to involve animals.

Amy So, can you explain a bit about your research and how animals figure into it?

Rebecca Sure. Most clinical chemotherapy has many terrible side effects because it damages healthy tissue as well as cancerous tissue. I’m developing new tools for cancer drugs that actually target tumors specifically. The way they work is pretty cool. Until the drug gets to the tumor, it’s “off,” so it isn’t killing healthy tissue. Once the drug gets to a tumor, we turn the drug on by shining light on it. The light makes the drug release damaging free radicals into the tissue, in this case, tumor tissue, around it. (Its called photodynamic therapy if you want to look it up.)

Amy So how do animals figure into that?

Rebecca Right. We first test the compounds on cell cultures, but as you can imagine, a bunch of cells in a dish is way simpler than the complex and diverse environment found in tumors in the body. Sometimes cells can be used as a screening method to identify promising therapies, but sometimes the environment around the tumor is crucial for the drug to work, so a drug that seems totally useless in a dish might actually kill tumor cells in an animal. To get a better idea of the efficacy of the therapy, we test the compounds on mice.

Amy Mice with cancer?

Rebecca Yeah, sometimes the mice get tumors spontaneously, sometimes we inject mouse cancer cells into mice, and sometimes we give mice cancer by injecting them with human cancer cells. Injected cells then grow into tumors.  

Amy So sometimes you’re testing these molecules on human tumors growing in mice?

Rebecca That’s right. The mice we work with are immunodeficient, meaning they lack much of their immune system. If their immune system were intact, their body would fight the foreign human cells we injected, like transplant recipients sometimes reject their new organ.

Amy Are the mice naturally immunodeficient or do scientists make them that way for their studies?

Rebecca As I understand it, a genetic mutation causing immunodeficiency arose by chance in laboratory mice in 1962. But they have certainly been carefully bred and cultivated. Now there are many different kinds of immunodeficient mice, I’m not sure what the origins of all of them are.   

Amy Wow, I had no idea. So you inject the tumor cells into the immunodeficient mice, and then what happens?

Rebecca It depends on the experiment. We’ll image the mice, administer the therapy, and watch the tumors grow or shrink. Eventually, the experiment ends and we have to sacrifice the mice. We save their organs for further analysis.

Amy And how do you feel about that?

Rebecca I thought I’d try it when I started in my current lab. My professor was very accommodating, allowing me decide my level of involvement with animals. After a few years of working with animals from implanting tumors to sacrificing them, I don’t feel great about my involvement. I still think it needs to be done, but I’m not as enthused about doing it myself. When I start my own lab (fingers crossed) I won’t include animal research.

Amy If you feel the work needs to be done, why don’t you feel okay doing it yourself? That seems hypocritical to me.

Rebecca Well at first I felt that if someone had to do the animal work, it might as well be me. I know I will be respectful to the animals, and only use them when necessary. As I got deeper and deeper, it just got to the point where I couldn’t stomach it. But even though I can’t do it, I believe the work is necessary to advance the field, and I respect the people who can do that kind of work.

[Intro Music]

Amy– Episode intro Hello, and welcome to Sit’N Listen: a production of Science in the News. We’re a graduate-student run organization at Harvard University that catalyzes discussion between scientists and other experts and enthusiasts. I’m Amy Gilson, a producer of Sit’N Listen and also a graduate student. I’m studying how proteins evolve using computer simulations, data analysis, and experiments in bacteria.

Mashaal My name is Mashaal Sohail, and I’m a PhD candidate in systems biology at Harvard. My research is focused on studying natural selection in modern humans.

Michelle My name is Michelle Frank, and I’m a PhD candidate in neuroscience here at Harvard. My research is focused on the auditory system. Over the course of my scientific career so far, I’ve worked with fruit flies, worms, fish, mice, and humans.

Alex And I’m Alexandra Schnell. I just started my graduate work in immunology, and I’ll be working on autoimmune diseases using mouse models.

Amy Today we’re going to squeak, sniff, and fly our way through the ways nonhuman animals participate in research, whether they know it or not. I say, ‘nonhuman’ animals because, of course, humans are a kind of animal, too. If we weren’t studying them wouldn’t teach us so much about ourselves. Not that plants, bacteria, and viruses aren’t interesting to scientists. For example, it was by studying the bacterium E. coli that researchers began to understand how cells copy their DNA. DNA replication works similarly in all organisms, but what was learned in E. coli can’t be applied directly to humans because there are some big differences as well. We’re going to be returning to this problem of importing knowledge from nonhumans to humans throughout the podcast, but this is basically the last you’ll hear about bacteria. It’s not that we’re anti-bacterial, but we’re also examining when ethical obligations we feel for humans should be extended to other organisms. As you’ll hear, this has been debated for thousands of years. But with bacteria, this piece? Not so worrisome. In my research, I grow many liters of bacteria, then destroy them as part of the experimental. However, not everyone behaves so brashly to the humble bacteria. People of the Jain religion extend a principle of non-violence to bacteria as well as plants and animals. So they would typically avoid eating yogurt to spare the bacteria in it. Culture plays a big role in the debates we even think of having.

Amy– Breadth of scientific uses of animals In scientific experiments animals are often enlisted as stand-ins for humans where it wouldn’t be right or practical to experiment on people. Rebecca works with animals in this way, and any drug on the market was tested on several animal species first.

However animals are involved in research in many different ways, even as sources of raw materials. For example, I work with E. coli, but I still use an enzyme that comes from rabbits to perform a particular chemical reaction. There’s this old paper from the 50’s or 60’s that describes how to grind up the rabbit muscles and do all these extractions on the mush to get the pure protein.

Michelle Scientists also work with animals just to understand animals themselves, whether in their natural habitats or in laboratory environments. For example, in one study, researchers put a rat in a situation where it could free a cagemate from a trap. But the cage was designed so that the free animal would be afraid to go open the trap. In these experiments, the free rat became less afraid of the trap over time, and eventually figured out how to open it. The experimenters also tried giving chocolate to the free rat, and observed that it would consistently wait to eat the chocolate treat until it had freed the cagemate and could share it. Studies like this are often interpreted as discoveries that human-like moral and cognitive abilities extend to animals.

Mashaal– History of animal research Indeed. Humans have actually been observing and dissecting animals to understand their behavior and biology and to advance medical practices since the time of the ancient Greeks and Romans, and ethical issues surrounding animal research go back just as far. Ancients greeks even dissected dead human bodies for medical insight. This was quite flickering and disappeared entirely with the widespread introduction of Christianity marking the human body as sacred. Ancient Greeks would interpret their dissections through the lens of the Hipprocratic theory that all humans are made of four distinct bodily fluids or humors. You could end up with an excess or deficiency of one or the other humors leading to maladies.

However, the prevailing view that animal dissection could yield medically relevant knowledge was replaced by the Empiric School in the 3rd century BC. This school of thought held that pain and death so change an animal that knowledge gleaned from studying them could not be clinically relevant.  

Later, during the Roman empire, Galen attempted to model anatomy through experiments once again. Not being allowed to dissect humans, he went for apes and other animals he considered close to humans. His models formalizing those of the ancients remained established for the next 1400 years.

In the Middle Ages, the experimental practices that gave rise to the great ancient physicians mostly stopped being practiced in most of Europe.  Increasingly christianized, eternal life became more of interest than scientific and medical endeavours. Elsewhere in the world though, the practices of the ancient hippocratic physicians were being resurrected by new translations into arabic.

Amy Right, science was flourishing in the islamic world during this period. For example, the path of blood’s circulation through the heart was discovered by Ibn al-Nafis, a Syrian physician working in the 13th century. This particular piece of knowledge didn’t make it into European science until it was independently discovered again about 300 years later.

Mashaal Good point, and we’ll talk about this second discovery again soon. Animal research picked up again in Europe in the 14th century, the beginning of the Renaissance, barreling into the scientific revolution. Rene Descartes, a French philosopher and mathematician born in 1596, developed an extremely influential theory that animals were like small machines, unlike humans, which have souls. This theory is similar to previous ones stretching back to the ancient Greeks, which held that humans were closer to God or the gods. However it was different in important ways, as well. By characterizing animals as machines, Descartes began moving away from the vitalist theory that living things are governed by different principles than inanimate things. This was a justification for the scientific study for animal research and was also used as a moral justification. If I got this right, Descartes believed that animals could have sensations and perceptions, displaying pain reflexes, for example, but he drew the line at the characteristic he thought was crucial to the moral status of a being: rational understanding. During the scientific revolution, animal experiments were critical to William Harvey’s characterization of the circulatory system, along with many other discoveries.

Amy Harvey’s work was truly important, but I can’t help thinking how much time (and how many animals) would have been saved if there were international scientific conferences in the Middle Ages where Harvey’s great-great-great grandparent could have seen al-Nafis present his work.

Mashaal Centuries later, in the 1800’s, greater ethical considerations for animals coincided with the first clinical applications of animal research. Ethical considerations grew out of utilitarian philosophy, which, as formulated by Jeremy Bentham, held that pleasure should be maximized. From this vein of moral philosophy, it follows that a creature’s capacity to experience pleasure and pain–and not its capacity for rational thought–that determines whether it’s worthy of moral consideration. Physicians were also working hard to put their work on scientific footing during this time. That meant many, many dissections. Animal research had become increasingly controversial over the last couple centuries, and now in Britain, Anti-Vivisection Societies were formed (often by women), to stop cruel animal sacrifice that was perceived as clinically useless. The controversy around animal research was only second to the controversy around Charles Darwin’s newly presented theory of evolution. Darwin himself occupied a middle ground where many, probably all of us, still find ourselves. He loved animals but valued research, as well.

Amy Intriguingly, by showing how human and non-human animals could have evolved from the same ancestors and under the same evolutionary forces, evolutionary theory blurred the sharp line Descartes and others drew between them. Those committed to Darwinism saw mental and physical continuity between the animals, which both strengthened and undermined justifications for animal experimentation. On one hand, evolution could explain why discoveries in animals should be applicable to humans. On the other hand, if consciousness continues in animals, then ethical considerations applied to humans based on their consciousness would apply to animals, as well.

However, evolutionary theory did not only widen the circle of compassion, in fact, the reasoning often went the other way. Some people believed that Darwinianism provided scientific support for racist beliefs: some humans were more like other animals while others had evolved more sophistication and were genetically superior. Applying the biological principle of “survival of the fittest” to the social realm seemed to imply an hierarchy among humans that could justify experimentation on disempowered people. Nowhere did this line of reasoning have more dark and infamous influence than in Nazi Germany. Under the Nazi regime, doctors performed medical experiments on Jewish people and other ethnic minorities, using them to test drugs, poisons, and experiments that might prove their genetic inferiority. They also examined how these people responded to harsh environmental conditions as might be experienced by German fighters, essentially using people in concentration camps as models for German soldiers and citizens.

Decades earlier, in 1896, a bubonic plague epidemic broke out in Bombay, now called Mumbai. A scientist named Waldemar Haffkine was ready to test a vaccine for plague and got permission from the colonial government to manage the public health response to plague in Bombay. A similar plague broke out in Egypt around this time, but no more than 50 people died as the plague was controlled through sanitation measures. However, Haffkine resisted any attempts to control the disease that might confound the results of the vaccination tests. The vaccine worked but over 10,000 people died in the place Haffkine turned into his laboratory within a year of the outbreak. Anti-vivisectionists seem to have been critical of Haffkine’s experiments. Hellen Bouchier , for one, saw a continuity between humans and other animals being used as experimental materials for scientific studies in her 1909 article “The Uses to Which Men and Beasts Alike Are Put by the Men of Science.”

Mashaal Right around that same time Bouchier published that article, it was getting pretty hard for vivisectionists to push for abolition of animal research on the grounds that it was clinically useless. In the late 19th century, Louis Pasteur’s work establishing the connection between bacteria and disease had immediate and intense effects on public health. His experiments required infecting animals with human pathogens or wounding animals to test disinfected products. His findings promoted hand-washing and sterilization of surgical instruments. He also developed a rabies vaccine that catapulted him to international fame. By the time Pasteur was working, anesthesia had been developed, and he used it on the animals he worked with to minimize their suffering. Steps like these, as well as the practical gains achieved through animal experimentation, shifted efforts towards preventing unnecessary harm, which basically remains the paradigm within which most scientists and many animal welfare advocates work today. The replacement of dogs with rodents as favored laboratories species also muted criticism. The public considered mice and rats pests that were less worthy of moral standing.

Michelle I think that feeling holds true for researchers, too. In neuroscience, people used to do a lot of research on cats and dogs, but that’s been essentially phased out over the past few decades and replaced by research in mice or rats. Most researchers today would have a really hard time feeling comfortable doing research on kittens, even though that used to be pretty standard. I actually went to a talk a while ago where the speaker described a project he was interested in doing that would have to involve rabbits. The trouble was, he was having a really hard time finding anyone to hire who would be willing to do experiments on rabbits. And this change isn’t only because dogs and kittens are so cute – there’s also good reason to believe that these intelligent, domesticated species have a greater capacity to suffer during laboratory procedures than do rodents.

Mashaal That a great point, and emphasis on many animals’ capacity to suffer lead to a resurgence in opposition to animal research after philosopher Peter Singer’s book Animal Liberation came out in 1975. This book argued that current differential treatment of humans and animals was not based on different capacities of the different species. Rather, it was based on speciesism, treating one species different from others simply based on the species, in analogy to racism or sexism. The work of Peter Singer and other utilitarians on animal rights has been incredibly influential and animal ethics remains an active area of philosophical inquiry.  

Amy– Prevalence of standard laboratory species While there have been trends away from using certain animals, such as dogs, another trend starting in the 1910’s is that certain species became extremely popular to work with. Diverse organisms are still used in laboratory research, but the vast majority of them are just a few standard laboratory species: mice, rats, a worm called C. elegans

Alex Because they are so elegant.

Amy Exactly. The humble fruit fly, zebra fish, and just to throw the microbes and a plant in there for completeness, yeast, E. coli, and the plant Arabidopsis. When a scientist wants to carry out a study, which of these organisms they pick isn’t just a crap shoot. For example, C. elegans is especially useful for neurological studies because its whole neurological network has been mapped out. And we’ll hear more about flies and mice in a minute. These species aren’t just a little more popular and other laboratory animals, they are a lot more popular. Europe keeps the best statistics on animal participants in research…

Alex …specifically, non-human vertebrates

Amy Yeah, so if we fly over to Europe

Alex It’s beautiful this time of year

Amy And by fly, I mean we’ll pull up the most recent “Report on the Statistics on the Number of Animals used for…” ok, this name is too long, we’ll link to it in the show notes. The the total number of animals used for experimentation and other scientific purposes is… any estimates?

Alex Well, given that my lab uses about 1000 mice a year and there are probably 100 labs at Harvard using mouse models, that gives us about… 100,000 per university? And let’s say there are maybe 100 universities and other institutions in Europe using animals in their studies that’s about 10 million mice at academic institutions? But then there’s biomedical industry, which I’d guess is even bigger than the universities, so maybe they use 20 million mice. Total that up and my final guess is that European labs use 30 million mice. Mice are extremely common research animals, so let’s guess they make up about 50% of all vertebrate animals who get drafted into research. Okay, so my final estimate is 60 million animals used in research.

Amy That’s really not bad, when I tried this I ended up guessing 100,000, but actually, that number is about 11.5 million.

Michelle Wow, I would have come up with a much higher number because my lab typically euthanizes about 2,000 a year.

Amy Wow

Michelle In labs that are doing much of any genetic work, most of the mice that pass through your hands will be euthanized because they are the wrong genotype, we’re looking for mutations that are pretty rare.   

Amy Yeah, that would have put your estimate at 120 million animals are used. I’d guess the lower actual number reflects variation between labs and also that most of the other species used reproduce more slowly than mice and are therefore more costly to work with in large numbers.

Overall, I don’t know if 11.5 million sounds big or small to you, but if you want to compare that with something, the number of animals slaughtered for food consumption is about 7 billion in Europe. (and it’s a similar figure in the US for that matter).

Alex Ok, so basically, a lot more animals for food than for research. How many of those 11.5 million are mice?

Amy 61%, or 7 million, are mice with rats pulling up a frankly distant second at 14%. If you want another measure, mice, E. coli, and Drosophila have each been the subject of a book tracing their rise as important laboratory organisms and the discoveries that have been made by studying and manipulating them.  

Michelle– What is a standard laboratory organism If that list of creatures Amy was just talking about sounds a bit bizarre—and perhaps none too appealing—you’re not alone. After all, mice, flies, rats, and E. coli aren’t generally considered high-class species, and most of these animals have a certain reputation for making their homes in garbage heaps or sewers or dirt. So how did they come to be such productive generators of new scientific knowledge?

For many of these models, their natural tendency to live around humans actually greatly contributed to their utility as lab animals. Their proximity to researchers made them easy to capture, and because their natural habitats were urban areas or human dwellings, they were easy to keep in the lab.

Of course, as we already discussed, there’s also a difference between a laboratory animal and a standard animal model. While scientists use animals in the laboratory for many different reasons, standard laboratory models are a special subset of lab animals. Standard animal models are almost always custom-bred for research, and tend to come in very specific strains or genotypes to help researchers around the world achieve consistent results in their studies. Many resources–both in terms of pre-existing knowledge and experimental tools–are available to scientists who work with these standard animals. While many scientists researching animals do so to better understand a particular species’ physiology or behavior, researchers using standard animal models often use them to study human diseases or to research aspects of biology they hope will generalize to other systems or species. To see how a species might make that transition from laboratory animal to standard animal model, let’s focus on the fruit fly, Drosophila melanogaster.

According to historian of science Garland Allen, the fruit fly was first brought into the laboratory around 1900 by Charles Woodworth, a graduate student conducting his thesis work with Harvard geneticist William Castle. Woodworth and Castle were looking for a way to study inbreeding, to figure out what kinds of changes can happen to organisms when they mate with close relatives over many generations.

Amy Haha, why would they be interested in studying mating between close relatives?

Michelle Eh, long story. Basically, people were studying inbreeding a lot in the early 20th century because there was a resurgence in interest in genetics, and inbreeding was a helpful tool for studying genetic inheritance.

Now, a small, rapidly reproducing insect was a promising way to study heredity. It didn’t hurt that Drosophila were easily available, either: Woodworth captured wild Drosophila around the laboratory and grew them in cultures of grapes and bananas. Biologists at other institutions soon followed Woodworth and Castle’s example and began working with the small fly.

Many of these early researchers were drawn to the fruit fly for the same reasons it continues to be a popular model organism today: it is small and hardy, making it easy and inexpensive to keep in the laboratory; it also reproduces quickly, making it ideal for experiments on heredity, evolution, and genetics. As historian of science Robert Kohler recounts in his book Lords of the Fly, researchers at the turn of the century were also eager to try working with new species. Many biologists at that time considered themselves “comparative zoologists,” and made a point to work with many different species, a practice that is much less common today.

Still, within a few years of its introduction into the laboratory, Drosophila was transformed from a wild insect to a workhorse experimental model, and several laboratories studying comparative zoology began to transform into dedicated fly labs. The most important of these labs was run by Thomas Hunt Morgan at Columbia University.

Alex What do you mean that fruit flies were changed from wild animals to experimental models? Are fruit flies in the lab somehow different than fruit flies in your kitchen? Or did researchers just start thinking about them differently?

Michelle Great question! As it happens, a bit of both. Shortly after they were introduced to Drosophila, researchers in Morgan’s lab started breeding them to extract specific traits that made it easier for them to conduct their experiments. They created “standard,” in-bred lines to reduce genetic variation, so that it would be easier to compare experimental results across different flies. Essentially, they were able to make a population of flies with very similar genes, which meant that these flies also had very similar traits and behaviors. When they identified mutant fruit flies, they carefully cultivated larger populations of flies with that particular mutation, until they had many different fly strains with unusual genetic mutations. In the wild, this kind of selectivity can’t happen: flies with an unusual eye color, for example, don’t only mate with flies with the same unusual eye color, so these abnormalities rarely spread to entire populations. But these early Drosophila researchers could make that happen.

Fruit flies also became gradually decontextualized from their natural ecology. Scientists began to think of them less as insects occupying some niche in a natural ecosystem and more as a kind of technology for conducting experiments and generating general knowledge about biology. Essentially, this shift took researchers away from studying the biology of fruit flies themselves and towards using fruit flies as a way of understanding broader biological questions. Which is not to say that researchers working on fruit flies or other model organisms forget that they’re working with animals. It’s more that these are special animals that inhabit a laboratory ecosystem, rather than the natural environment of their ancestors.

Morgan and his colleagues were also careful to share both their knowledge and their experimental tools freely. They willingly shared their various mutant fly stocks with other researchers, which helped promulgate the study of fruit flies by other labs. Morgan was also a leading researcher before his group adopted the fruit fly into their lab, and his group was quickly able to use the fly to make many key discoveries about genes and genetic inheritance. These discoveries—which led to a Nobel Prize for Morgan in 1933—also contributed to the legitimacy of this new animal model.

Mashaal Do you think researchers could have made these same discoveries in a different model system?

Michelle Eventually, yes. Several early breakthroughs in genetics also happened in corn, for example. But growing corn is slow, and growing fruit flies is fast. Fruit flies are also much easier to grow, which makes it easy for other labs to start working with them. Growing corn requires large amounts of space and a fair amount of good weather – both of which can be hard to come by.

Of course, Drosophila melanogaster is not the only small animal that reproduces quickly. There are even plenty of other Drosophila species that have similar traits, and they probably would have been just as effective as melanogaster. But melanogaster was the first. Researchers needed the inbred and mutant strains to do their studies, and once those had been established in one species, there was little reason to start doing all of that over from scratch.

Today, there’s even more reason to stick to well-established animal models. The most important animal models have all been around for over a century at this point, so there’s a lot of existing knowledge for researchers to build on. Decades of researchers have also crafted extensive research tools for each of these core model organisms, and most of these tools don’t transfer very well between different species. An experimental technique that works extremely well in mice, for example, might not work at all in fruit flies. So, for many kinds of work, it’s beneficial for researchers to pool their resources into a small number of experimental models, rather than establishing tools and resources independently for many different species.

Amy As we mentioned at the top of the show, there was really so much to say about animal experimentation, it’s such a big and multifaceted topic, that we needed to split this episode into two parts to stay in our normal half-an-hour range. So we’re going to leave it there for now. In Part Two, we’re going to pick up with flies and dive into the science that has come out of fly work. Did you know there are fly models of autism? Crazy. There’s a lot more to come including how to make a mouse pee and we’ll speculate on the future of animal experimentation.

But before we sign off, I wanted to give you updates on GMOs and CRISPR from previous episodes. In episode one, we mentioned congress was considering a bill that would block states from passing laws requiring GM products to be labeled. We can now let you know that this bill failed. On the other hand, the Professor Niakin’s bid for approval to edit human embryos using CRISPR was approved in Britain. Finally, if you listened to our last episode on mosquito control, you might be interested to hear that a new method using bacteria that render specific mosquito species sterile or unable to carry dengue are being tested. If you haven’t listened to our last episode, hopefully that piqued your interest. Finally, just as we were preparing the episode, the NIH lifted its moratorium on human/animal chimeras i.e. animal embryos with human stem cells injected into them. Oh man, so much more to talk about but we’ll have to leave it here for now. I’d like to thank Professor Lesley Sharp for our conversation around research and animal technicians’ attitudes towards animal research and to acknowledge the article “Animal Experiments in Biomedical Research: A Historical Perspective” by Nuno Henrique Franco which really helped us understand the history of animal research.

Michelle We’ll be back soon with part two of this episode and more: on the possible reproducibility crisis going on in science research now, and on oceans, which will be recorded live in collaboration with the Radcliffe Institute of Advanced Studies. In the meantime, we want to hear your thoughts on science and animals; and your suggestions for the podcast. E-mail us at sitnpodcast@gmail.com or tweet @SITNBoston. If you liked today’s show, definitely subscribe on iTunes and leave us a review.

We actually just got our first review on iTunes: PattyBiologist wrote “I’m loving it! It’s nice to have a podcast that goes into some depth on an issue rather than just skimming the headlines” and gave us five stars. Thank you so much PattyBiologist we were so totally stoked to get your review. Everyone else, if you leave us a review maybe we’ll read it on the air too. Positive reviews help others find our podcast and we’ll really grateful for any feedback you share with us. The SITN blog and this episode’s show notes can be found at our website http://sitn.hms.harvard.edu/
Until next time…. (Listen to Part Two here)

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