The Tiny Fish That’s Changing Modern Medicine

When you look at a zebrafish, you probably
just see a cute, tiny fish that’s smaller than your pinky finger. But this little fish is so much more than
that. You’re looking at an amazing scientific
tool that has led to some major discoveries. Zebrafish have been used since the 1970s to
study the development of vertebrates, and more recently, they’ve been helping scientists
learn more about human diseases and maybe even develop some potential treatments. So why the zebrafish? Well, like all fish, their genomes are similar
to the human genome, mainly because we share a common ancestor. They have over 26,000 protein-coding genes,
and about 70% of those genes are related to similar genes in humans. Since zebrafish have been studied so much,
we know that around 80% of the disease-causing genes that have been identified in humans
have at least one related gene in zebrafish. By studying what these genes do in zebrafish,
scientists can learn more about what they do in humans. And there are other reasons researchers specifically
study zebrafish: They’re cheap to maintain, and the females
can spawn around 200 to 300 eggs in a single week, which makes for a lot of new test subjects. More importantly, zebrafish embryos and larvae
are transparent and develop really quickly. There’s even a genetically-engineered strain
of zebrafish that’s transparent through its whole life. That transparency allows researchers to see
exactly what’s going on inside the fish’s body, and watch biological processes — like
how cancers develop. That said, zebrafish still aren’t the perfect
model for human disease — for one thing, they don’t have lungs or mammary glands. Plus, a lot of their genome is made up of
duplicate genes. Some of those gene copies might have mutated
and developed functions that weren’t there in the ancestor’s gene — which would make
them different from the human versions. Even so, zebrafish have been able to help
scientists learn about a lot of different diseases — like melanoma, the most dangerous
type of skin cancer. Cancer develops because of mutations in specific
genes that affect how cells multiply and die. And the most common mutation related to the
melanoma is called BRAF(V600E). Zebrafish that carry this mutation, and also
lack a tumor-suppressing gene, make good models for the disease. So researchers can study how cancer develops
in fish with the BRAF mutation, and use them to test treatments. They’ve also used zebrafish to find other
melanoma-causing genes. See, sometimes, the BRAF mutation just causes
benign moles instead of melanoma. BRAF might start the process, but another
gene has to cooperate to actually cause the melanoma. The question was how to find that gene. The researchers used human melanoma samples
to look for duplicated genes that might cause cancer along a certain section of a human
chromosome. The duplicated genes they found were then
inserted into the genomes of zebrafish with the BRAF mutation. And only one gene, called SETDB1, was found
to accelerate melanoma formation in the zebrafish. This discovery might lead to the creation
of new cancer therapies that target SETDB1. Zebrafish research might also be able to help
with stem cell transplants. And the reason for that has to do with a compound
called prostaglandin E2. In a study, researchers discovered that when
certain chemicals were used to enhance prostaglandin E2 synthesis, the amount of hematopoietic,
or blood, stem cells in the zebrafish increased. So, extra prostaglandin E2 might be able to
help treat someone who’s getting a blood stem cell transplant, like a leukemia patient
or someone with a blood or immune system disorder. Which is great news! This discovery eventually led to the creation
of a drug called ProHema that’s supposed to improve the success of hematopoietic stem
cell transplants using blood from umbilical cords. Between 2014 and 2015, it went through stage
II clinical trials where it was tested on patients to see how well it works. And the results are pretty promising. In patients who were taking ProHema, stem
cell transplants seemed to start working earlier than the control group. So, ProHema might help improve the effectiveness
of these stem cell transplants, but it still needs to be tested more. A specific trait of zebrafish might also help
scientists with regenerating human tissue. If a zebrafish heart gets damaged, it can
regenerate. Even if part of the heart is removed, it’ll
just form a clot at the wound site, which eventually gets replaced with new cardiac
muscle. But if part of a human heart gets damaged
— like from a heart attack — the damaged area generally just turns into scar tissue,
which doesn’t pump as well as healthy tissue. If you could regenerate healthy cardiac muscle
instead, you could avoid that permanent damage. While it’s still being studied, it seems
like the reason zebrafish can do this and we can’t is because the injury activates
their cardiac muscle cells, which then regrow the tissue. As scientists learn exactly how that’s done,
the idea of human tissue regeneration might get closer to becoming a reality. So the zebrafish may be tiny. But it’s helping modern medicine in a big
way. Thanks for watching this episode of SciShow,
which was brought to you by our patrons on Patreon. If you want to help support this show, just
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  1. Nine blinks in 4 minutes and 32 seconds. I know there's cuts and editing, but it's still impressive. Impressive enough to trigger my brain into asking whether or not you blinked at all.

  2. wow, the universe is crazy, i really secretly wish people in science talked about god more cause we are so cleary the universe itself created to experience itself, and when we literally are, as individuals, connected to the whole, isn't that god?

  3. Actually the gene-mutation idea about cancer may not be correct. The cancer aneuploidy theory may actually be more correct. This has to do with chromosomal abnormalities.

  4. I detect overly conservative white guy styling decisions involved with the creation of today's hoodie.
    I Vote for all styling decisions of this channel to be given to Mr Aranda. White guys have no style, no edge, no flavor. Live vicariously through those that posses a little more skill in a different area.
    -A White Guy

  5. The smartest people in the world are figuring out ways to make the dumbest people live longer. Cool. "Welcome to Costco, I love you" -Brought to you by Carl's Jr.

  6. it's interesting how I have less trouble with the cognitive dissonance of "I don't want animals to suffer" but "I want to eat animals" than with "I don't want animals to suffer" but "screw it let's give them cancer anyway". Like giving cancer to a fish so that we might cure it in humans was more harmful than simply not eating them. Like, my brain seriously associate humans having cancer with something less horrible than me not being able to eat meat. That's really disturbing.

  7. Monash U.

  8. a few years ago during my undergrad I applied to be part of a research team looking into zebrafish neurophysiology, too bad I was a bio major and it was a psych study so they rejected me 🙁 would have been really cool to be a part of it

  9. Yeah it's ok, zebra fish lay so many eggs let's inject em some uggly tumors and deseases and kill a all bunch of em. Those stupid fish are so tiny and don't even have lungs right, who cares ? Its not like it was wrong or anything

  10. 0:26–0:31 "because we have a common designer" is also a good explanation. Better infact, considering the flaws in nearly all of the "pillars" of evolution.

  11. probably over 10 years ago now, back when I was in junior high, the school organized some special project where the students were paired with researchers (all were biologist of different sorts if i recall correctly) and required to make a presentation about the research subject. I was paired with a researcher that was injecting zebra fish with some weird genetic material that would light up the area it affected with either bright green or red color (depending which was used) into egg cells . The goal was to find which gene in the fish was responsible for the development of nervous cells to find a way to help Alzheimer patients and the like.

  12. Why do shots hurt so freakin much?
    And why some more than others?
    sincerely, guy who hasn't been able to move his arm for over 24 hours

  13. Hey sci show, while creeping around my house at night to grab a midnight snack I was tiptoeing to try and not disturb anyone. while I did this I first thought "why does, no matter how softly I plant my foot, does it always my noise?". Then I remembered that any two objects field of electrons prevent them from ever really touching which brought up a second question " why does two objects that never really touch coming together make noise and why would slowing the speed of the objects lessen it?" Could you please answer on or both of these questions for me?

  14. I think you guy's talk too fast. I'm a Molecular Genetics Undergrad fluent in English (or at least I think I'm fluent) and even I had to re-watch some parts to understand everything completely. I know the narrator has a lot to cover on every topic but talking too fast just points to the fact that you're really just reading the words from a screen. Love what you guys do here but seriously, slow down.

  15. I'm surprised he didn't mention Glofish, which are fluorescent zebrafish that were originally used in research, but then became commercialized. They're the first GMO animal you can own as a pet and they're found in big pet stores and local fish stores.

  16. What if we're just the zebra fish of some alien race of scientists? Or even ourselves, from the future, with robot bodies!

  17. Did Doctor OZ make the title of this video? THIS FISH IS A CURE ALL! And then many idiots proceed to buy the useless and not scientifically proven product.

  18. my son has a one of a kind genetic mutation. because of the lack of a second person being diagnosed with the same disorder. Doctors have made zebra fish that have the same genetic mutation as him so they can learn more about it.

  19. What is the common ancestor that links humans and fish? Can someone post a link to a site discussing this topic?

  20. The fact that we share a common ancestor with these fish sadly means that creationists can never use medicine or treatments derived from this research. It goes against all they stand for.
    Yea. That's sad…… But hey! More for us, right?!

  21. why did Germany produced so many(!!!!!) good mathematician and physicists in 19th and 20th century???? do a show on that please

  22. Yes, all that stuff the fish has we can put in us, and soon we will be healthy, and we can breath underwater also. A win win solution.

  23. I think that using animals to understand and discover new ways to treat a person health is important. There are so many animals out there in the world that we have no idea why they exist or what benefits they provide to the environment. Well one of them is the zebrafish or Danio rerio. Genetic testing of these fish could provide humans with a solution to some medical issues, specifically diseases. With the similarities between humans and the zebra fish, scientists can possibly develop a better understanding of how certain diseases work and how they are passed on. Such things can be vital to patients that may be suffering from a disease that doesn't necessarily have a cure or fix at this time. By using animals and conducting research on them, I think it creates a whole new avenue for medical knowledge and discovery to follow.

  24. OHHH!" a common Ancestor.." There we go with the stupid, manure EVOLUTION smoke pipe THEORY and not facts (Never has anyone found a single "missing link.") I would like to see just one person EVOLVE into something other than a peerson. Read your Bible and find TRUTH!! You want to know where the Platypus came from. During the amoeba's climb out of the primordial OOZE, the ancestors of the original Amoeba changed their minds, if they had one yet, and at different times during the evolution, and now we have such a mixed up animal, it defies logic.

  25. I really like this idea of using zebra fish as a model organism to study diseases, way better than using fruit flies. I never knew of the genetic similarities between humans and zebra fish and by the sounds of it can lead to amazing breakthroughs. I agree with all of the cancer and disease research that can come from these fish but learning to regenerate human tissue is going a bit too far. Scientifically I know that it will eventually be done but ethically it messes with human DNA and is like playing God. I think that humans can try to learn about and treat diseases and cancer but once they try to change how the human body operates, there needs to be a line drawn.

  26. Come on! Everybody are already deadly tired of this kind of medical announces! You accomplish something first and only after this make the loud statements. How many times all of us heard about this kind of "huge medical successes" on the way which turned out to be nothing more than just a HYPE. Fuck off with your lies!

  27. Count on. Democrats to ban testing on zebrafish by declaring zebrafish endangered and animal testing contributing to global coo… global warming… err…cimate change. Money otherwise going to research will be used to pay for illegal aliens instead.

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