Welcome back to Nature League!

One of the best parts about making videos for you is reading your comments about new and interesting topics that we can learn more about together. In the comments section of our great white shark genome video, Tyler mentioned the topic of model organisms and how research relies on them.

This is an awesome topic, and one that is rapidly changing thanks to new advances in gene editing. More on that later... But first, let's discuss what model organisms actually are.

Spoiler alert -- it's not when Sweet Baby Jane is looking particularly beauty and I take enough photos of her to fill up my phone's entire memory card. To understand model organisms, we should start with research organisms in general. Research organisms are any non-human individuals that are used to study something about life on Earth.

The organism used depends a lot on the question being asked -- for example, if a scientist is interested in learning about the regeneration of tissue, they might study a species that's able to regrow body parts. There are several general definitions for model organisms, but the one I like to use is aligned with the one provided by the National Institutes of Health here in the U. S., and it goes something like this: what makes a model organism a model is that they're used as a sort of convenient shortcut representative, or model, for understanding not just biology, but the biology of humans.

The list of model organism species is a bit shorter than the list of species used for general biological research, and that's because certain characteristics are used to work as a proxy for human health and function. To start with, model organisms need to have a similar enough biology to that of humans in order to be useful to scientists. And it doesn't have to be an entire body plan -- even having similar cells or biological processes is enough to be useful as a human proxy.

In addition, model organisms need to reproduce and grow quickly enough to see the effects of experimental treatments over time. A disease in a human might progress over decades, but in a fruit fly, it could take days. And overall, model organisms need to be hardy and very good at living in various conditions.

Which, you know, makes sense when you think about the time and resources that have to be put into keeping these individuals alive long enough to actually gather data. Now, I have a lot of conflicting thoughts concerning the scientific usefulness and ethical considerations of model organisms. Instead of going back and forth inside my own head,.

I figured I'd have the conversation out loud. So, it's time for a segment called “Brit vs Brit”! [BRIT 1:] Alright, so, model organisms. [BRIT 2:] Yep! And you're sure we're not talking about when we take way too many pictures of Baby Jane being, like, super cute in her safety shark?

Yes, I'm sure, we explained that earlier. Alright, cool. So you're talking about species like fruit flies, stuff like that?

Exactly. Fruit flies are a super common one, but there are a lot of other classic ones as well. I'm thinking about E. coli, baker's yeast, the nematode worm, and the mouse for sure.

Oh, and don't forget the mustard plant, zebrafish, and frog -- those are used all the time, too. Definitely, though I do wonder why we spend so much time and effort on just a few model organisms. I mean, I think it makes sense.

Just think about what each one has contributed in terms of knowledge. Yeast helped us figure out how cells divide. That's no small subject.

Fruit flies helped us figure out chromosomes! That changed the entire course of biology. I know, and I'm not discounting that.

It's just that I wonder how this actually translates into humans. Like for example, there will be new studies published, and it's all like, "Wow, we found this new treatment for cancer, and in the end, it's all like, “...in mice”. Yeah, but “in mice” is close enough, as I mean we're both mammals...

I find these results really exciting. I'm not so sure. I mean, big issues have come up on studies using rhesus monkeys, and they're way more closely related to us than rats and mice.

Ohhhh yeah, I remember that. That was that leukemia drug, right, which was really promising in monkey subjects -- -- but then every human subject that took it during clinical trials almost died. ...yeahhhhh. And besides, I wonder if some of the most basic biological questions that can be answered by model organisms have already been answered.

Plus, when it comes to using model organisms in biomedical research, I mean, wouldn't it be more interesting to dig into actual human disease and actual human biology? Well yeah, but it's not that easy to just study humans, right? There are ethical considerations.

What, like there aren't ethical considerations for non-human species? Well I mean, those ethical pieces have already been taken care of for those species. There are a ton of regulations at private institutions and research universities for the caregiving, usage, and treatment of model organisms and lab animals.

You're right that we've come a long way, and there are definitely regulations in place, but there's something to be said for the ethical considerations of consent. Plus, there's a new scientific trend where scientists are using gene editing to make novel model organisms, and those are not doing well in the lab. You're talking about that Nature News report about CRISPR, right?

Right. You've gotta admit that new direction is pretty rad. I mean, recently the U.

S. National Science Foundation put in $24 million into the research and development of new model organisms. And in March of 2019, people reported that they'd actually for the first time made a genetically modified reptile.

Yeah, but you're leaving out the part where scientists are currently really struggling to keep these new model organisms alive. Species with incredible features that make them so sweet to study typically makes it to where they don't do well in lab conditions -- living in specific, unique environments probably led to those features in the first place. Natural selection.

Got me again. I always do. Anyways, I think I'm just a bigger fan of some other options on the table.

Like what? Like in vitro cultures, for instance. That's where we take cells, tissues, other biological molecules and study them outside of their regular biological housing, like in a petri dish instead of inside of an organ, or inside of a live animal.

Fair point -- those have come a really long way. Totally. And there's enormous potential now to use really sophisticated computer modeling and software to get at some of these answers.

Sure, but let's be honest -- model organisms are always going to be around, because they're the place where the development of new technologies even begins. You have to start somewhere, and the simplicity of the few excellent model organisms we have have allowed us to come as far as we have in science. Like I said, I have many thoughts regarding this issue.

While it was fun to play both sides of the argument, my personal view falls somewhere in the middle. I am amazed by how much we've learned from just a few species, and thankful for that knowledge and how it helps the human species overall. However, I do worry about the ethical considerations, and hope that we can continue to develop technology that allows us to bypass using animals altogether.

Either way, model organisms aren't going away any time soon in biomedical research, so hey -- might as well make ourselves knowledgeable about the nuances regarding the topic. Thanks again to Tyler for suggesting this topic, and to all of you who engage with us in the comments and on Twitter. Keep them coming!

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