McGinnis is a molecular biologist and professor of biology at the University of California, and he studies the evolutionary changes in transcription factors by looking at the Hox genes.
So let's just recap here; Old genes, like the teeth in the chickens, can be "turned back on". They had that gene because they evolved from dinosaurs. Scientists can interact with gene regulators, like putting an extra eye on the fruit fly. ... Do I have to spell it out? Where the hell is my Dinosaur theme park?
Amazing facts about Hox genes: 1. Sequence analysis showed that the homeodomain of one of the mouse Hox genes differs from Antp gene of drosophila by only one amino acid. 2. Similar mechanisms for segmentation occur in flies and mammals even though they are separated by some 600 million years of evolution. 3. Everything else about hox genes.
I wonder what would happen if we turned on all the regulatory genes in a human, i like to imagine we'd have superpowers but i'm guessing we'd look like something out of a horror movie.
Another question: When they did this messed up experiment and the fruit fly grew an eye on it's leg, did they test to see if the fruit fly could see from this new eye? ie did it have an optic nerve connecting to its brain? I assume not, since that would require more instructions to be sent to make the optic nerve also. Fascinating subject, I must know more.
And does that mean that we could maybe eventually create "super beings" that have features that enhance their function? like actual functioning eyes on the back of your head; or lots of mini brains that we have forced to grow inside of your thorax that will enhance your psychological abilities?
@@grinleef295 Oh god! That's like.. If I.. I can't even form this question. Right, so let's say we somehow make a human with an eyball(s) on the back of it's head, even if it's connected with the brain; how would it see if our brains aren't accustomed to 360 field of view? Or are they?? Would it be a 360deg view with blurred spots near ~160-200deg? Or would the image overlap in the front if you've got all your eyes open? Lets not even talk about the eyes on limbs...
There seems to be a contradiction between physics and biology. According to physics, nothing travels faster than the speed of light. However in RUclips comments, creationists have their arguments shot down in flames in what appears to be faster-than-light speed.
Im in college our professor just uses these videos instead of lectures. Literally that is it nothing else just a link to the video a discussion about the video and a weekly 25 question test that is word for word pulled from quizlet. 4,000 a semester well spent(sarcasm). Also this is not some low level community college this is a tenured professor at a D-1 school, and people wonder why our generation complains about the education system.
This is absolutely what I want to do with my life. I always have the hardest time trying to explain it to people, now I'll just show them this. I love being a scientist.
As usual it's a great video but the major mistake is listing homeobox and Hox genes as the same things. All Hox genes are homeobox genes, but not all homeobox genes are Hox genes. It isn't just a misuse of brackets, later in the video Hank says we have several hundred Hox genes in our genome, which is entirely wrong. If you Google "difference between Hox and homeobox" it'll be explained. I love Crash Course!
This guy is truly amazing! I've never thought that someone can combine science and humor and make it really interesting to listen the stuff which is normally boring to read about
i cant entirely blame critics of evolution as i doubt any person is equipped to truly grasp the length of time involved in such a process. and you wouldnt be entirely wrong either to say "its just a theory." but the fact remains that evolution is one of the best supported scientific theories in ever. there are absolutely heaps of evidence to support it and to say something like "call me when you see it happen" is to say: if two men go into an empty room with one door and no windows, one comes out with a hot gun, and the other is found recently dead of a gunshot wound from that same gun, no one can be found guilty since it wasnt observed.
My cockatoo is just a bird version of a 5 year old. If you hold it she wants it, and if you aren't looking at her she is mad. But give her 5 seconds and she will crawl up into your sweatshirt and cuddle with you.
I don't normally add something to my favorites list, but this video had me fascinated enough just with the potential for new discoveries that I had to do so. Thanks!
This was one of the coolest crash course biology episodes yet! Thanks for the comprehensive overview of such a cool field! The part about chicken teeth made my brain esplode!
Hoemobox genes are something I'm gonna start studying in A-Level Bio soon, so I thought I'd give this a rewatch. Thank you for making A-Level seem easier!
I love CC but Idk why they say at the end of their videos "if you have any questions ask us in the comments." I've never seen them in the comments whatsoever
Hank et al, Love your shows! Love 'em! But I am blown away by the amount of (let's call them crazy people) your videos attract, the kind who get offended by science because it doesn't support their religious teachings. I just wanted to let you know they're not the only ones watching. (What? They're not watching? They're just posting comments? ... oh.)
That's a bit disrespectful, and not really funny. It amuses me how both: -Some religious people (particularly monotheists) think they're so right about science (well, evolution) being all a load of tish-tosh. -Some atheists think they're so right about religion being flat-out wrong, and science being right. And they smugly like to point out that those of the above criteria are ignorant, uninformed and old-fashioned. Look, perhaps there're faults in both things (i.e. banking solely on religious scripture or scientific evidence). So can't we just be respectful (i.e. omit the "crazy kind" and the prejudices of the so-called 'eager' and 'stupid' religious believers who allegedly skim through scientific videos simply to post comments about science being wrong), and not infuriatingly smug? We all know the saying: "Pride comes before a fall." That being said, I agree that this show is awesome. Have a good day.
As someone in CS, evo-devo makes me very happy! It's kind of like computation is the last major paradigm shift in human understanding. After that, understanding new things becomes a recursive call to that paradigm itself.
When we watched some of these videos in class after taking notes about the topic, I was tripping over his words because he talked too fast. Now that the Bio exam is coming up, I'm binge watching all these videos, and it's absolutely amazing. These videos tie up everything I learned, and I am able to catch up with his pace very quickly since I know everything. I wish luck to those who are taking the Bio Exam in 2017!
Hackers show more respect for the coders than these guys! Amazing how they can't see the Truth staring them in the face. Too bad that Bush-appointed fed judge OUTLAWED EINSTEIN's views..."I want to know how God created this world. I am not interested in this or that phenomenon, in the spectrum of this or that element. I want to know His thoughts; the rest are details." OR "Every one who is seriously involved in the pursuit of science becomes convinced that a spirit is manifest in the laws of the Universe-a spirit vastly superior to that of man, and one in the face of which we with our modest powers must feel humble." Its good to see they're backtracking on "junk DNA" though...quietly.
I believe they mention (maybe this video or a previous one) that we begin our development with a tail and, I suppose, have genes that say "no tail at this point" for humans. It appears that all the embryos have a little tail when they start developing... and I'm pretty sure there are people that have longer spines that protrude like a tail.
Kendra Desmone I don't know about unethical but I'm sure there wouldn't be too many folks lining up for a tail... or, could be big business for the cosplayers at comicons. Lol! But, yea, we could possibly have tails :)
i am a Computer Engineering student(i love science! if you're asking why i am here) and this topic is pretty interesting. Those instructions, those genes triggering a chain reaction is like a computer microprocessor. It is made of bunch of transistors which are basically switches, different configuration of switches will make different logic gates, arrange them and triggering a single switch will trigger other gates and switches in a nanosec chain reaction that will eventually get the work done.
Hi if you don't believe in this, no need to troll. And no need for anyone to get in huge arguments. None of you are going to change anyone else's opinions
No need for you to tell people to stop posting conflicting opinions. And when you say no one will change anyone's opinions, you use the presuming omniscience logical fallacy.
No need for you to tell people there's no need to post conflicting opinions. In fact, there was no need for me to make this comment about there being no need for you to say there was no need.
I've already read about a lot of this a while ago in the book "How to Hatch a Dinosaur", but this video does a great job at summing it all up and making it seem really cool.
I started watching Crash Course in order to pass the final high-school examination. I still use it to revise for the uni exam, but man, I would watch this as a TV show before going to bed!! Thanks everyone who makes this possible, whether it be for us who need to pass the exams, or us who enjoy geeking out on stuff like this :)
DNAunion It's a rugged, well though-off and effective model with its own detailed terms and concepts that bases itself on the principle that explains the progress of life from basic to complex... would have been a waste not to take it.
You know that software engineers taken a note from nature, look up genetic programming, genetic algorithms and evolutionary algorithms, one can use these heuristics (techniques) to optimise programs and search for solutions to problems. Some, such as NASA, have also be used GA/GP in conjunction with Computer Aided Design to create machinery too.
Wait wait wait. So through manipulation of these regulatory genes, you can easily - relatively speaking - control where body parts are positioned. So we could, for example, genetically engineer humans with lots of legs that should actually function as human legs by, say, using a regulatory gene(s) from, say, a spider?
Well, number 1, that would be super unethical, and number 2, legs require a lot of other stuff to work like legs - a pelvis to plug into, a bit of backbone to tie the pelvis into the rest of the skeleton... In short, you could probably do it, but it would take a lot of very messy experimentation and a knowledge of genetics greater than what we currently know. You couldn't have settled for a 6th digit on the hand, could you?
Absolutely, but I'd like to just point out that you wouldn't need to take the hox genes from a spider to give a human more legs, you could just have multiple iterations of our own hox gene for legs! Like Hank said, the regulatory genes don't actually say anything other than "make leg here" - and lots of animals make legs with the *exact* same regulatory hox gene. Like mentioned, however, human legs need a pelvis and a pelvis is a pretty complicated structure. We could put lots and lots of legs on somebody but those legs would be very limited in movement and would serve no purpose other than to make life really, really difficult.
You could but it's not as easy as putting them in a fruit fly or something since humans are _waaaaaaaaaaaaaaaaaaay_ more complicated than flies, and no one would want the extra legs, and such
I struggle with all of science and have been watching these videos to try and better myself and i have to say this was definitely interesting, and really thought evoking thanks
Fantascinating...love it. One thing to note is that humans are also sometimes born with prehensile tails, an the snake is born with vestigial legs, or the chicken embryo has vestigial teeth.
so can we activate all dinosaur genes and then make something as dinosaur resembling as possible. also would that mean that chicken tastes like dinosaur?
Or you could just make a chicken grow a full tail, teeth and fix it's arms. www.creativereview.co.uk/images/uploads/2012/10/convenience_food_1.jpg www.inspirefusion.com/featherless-chicken/
Fantastic video. These are getting much easier for me to follow now and much more distinctive. Doesn't seem like as much of a mad rush. I understood the earlier videos, but I was never going to retain any of it.
Yes, you blew my mind! WOW! The beginnings of answers to questions I asked as a kid in school ... so many years ago that your parents might not have been born yet. :-) Not a lot of things make me want to be young again, but evo-devo makes me want to be a little nerd-kidlet again in today's era of scientific discovery. Thanks, Hank.
Damn, Our lord and Savior works in mysterious ways... I PRAY TO YOU EVERY NIGHT FLYING SPAGHETTI MONSTER LET YOUR NOODLEY APPENDAGES BLESS ME WITH HOPE
+Charlie Peterson: Um, what? Humans didn't evolve from reptiles, and spiders are not reptiles. In response to your, "So if you can turn on old regulatory genes that have been repressed through mutation... does that mean humans could redevelop reptilian traits? The Amazing Spiderman all makes sense now."
Kronimiciad No, mammals did not evolve from reptiles. There are two clades of amniotes: synapsids and sauropsida. Mammals evolved from the former whereas reptiles evolved from the latter.
DNAunion In other words we were all fish. If I remember correctly, and I am probably wrong, fish evolved into amphibians, then MAMMAL LIKE REPTILES so in a way Kronimiciad was right, but I said they were Mammal like Reptiles.
jacob nichols en.wikipedia.org/wiki/Pikaia (may be an ancestor of fish, or at least anatomically close to an ancestor of fish) en.wikipedia.org/wiki/Haikouichthys (may be an early fish)
I think this is the first episode that told me something really new. And it was awesome! Don't get me wrong, the others are great, too, to help me not forget all that stuff I read a long time ago... Keep spreading the awesome, guys!
To answer the second part of the question, the removal of earlier traits alongside new ones is enough to account for the speed of bird evolution. Additionally, many of those traits were already developing in raptors and their relatives. For example, they had strong legs for jumping. Feathers are first shown from the early Jurassic, millions of years before birds hit the scene.
"Fantastisizing!" Nice one. As a nursing student who is miserable in microbiology class, I'd like to thank you for making it more exciting, interesting and relevant. Please keep it up. DFTBA
4:21 Now you don't have to google it: Bill McGinnis is a molecular biologist at the University of California, San Diego. McGinnis studies the evolutionary changes in transcription factors by looking at the Hox genes. His main research has been comparing Hox genes between species to see if they are kept intact during evolution. One long term objective of the research in his lab is to understand the molecular interactions that underlie functional specificity in the Hox patterning system.
thanks so much hank!!!! your videos are the best introductory learning tools! always keeping it interesting and i have to admit i cant help but smiled a few times throughout the video at your nerdiness haha! cheers!
Homeotic genes also known a homebox genes are not the same as HOX genes as u stated at 2:54. They are different. A homeobox is a sequence of DNA within a gene. The protein that results from the gene will will include a small number of amino acids that are dictated by the homeobox sequence. This part of the protein is known as the homeobox domain (or just homeodomain). The importance of the homeodomain is that this is the part of a protein that can interact directly with DNA (or RNA). So, proteins that contain a homeodomain can act as transcription factors. Equivalently, genes that contain a homeobox sequence can be regulatory genes. Hox genes are simply one group of genes that contain a homeobox sequence, and which are very important in body plan development. However, there are plenty of other genes that are not hox genes and also contain a homeobox sequence.
It's always retained in the genome--certain genes just get "turned off" or "inactivated" (and thus the traits get unexpressed) or genes change through mutation. In order to get a new species with new traits, all you need to have is an altered genome. In the case of birds, they happened to get several genes turned off (ones that code for scales, tails, teeth, etc.) while new gene mutations called for the development of wings, beaks, feathers, etc.
There's some dripping water in the background of the video (intentionally). It's not annoying; I just noticed it and thought it was worth pointing out. Also I'm just as blown away by instantly giving chicken teeth as Hank seemingly was. That's incredible.
I love how Hank said "you PROBABLY haven't thanked your mom" because ya know Nerdfighteria and some people probably have actually thanked their mom for that
Really great video. You did an awesome job of explaining these new ideas and thoughts in biology. Not an easy task, new ideas are so often tumbled and tangled up in such a way that makes it especially difficult to sort, teasing the meaning of them out of them. Thank you very much.
I just watch this for fun, this was a very fun one! Such awesomeness! I watched a programme recently where a guy was looking at chicken embryos, and showing how they could basically make tiny chicken dinosaurs by re-surfacing those old features that begin in the development but aren't kept for hatching.
When I was a kid and I said I wanted to be a scientist, I specified Archaeologist and that I wanted to dig in the ground looking for lost pieces of our past. And I did, I am, and it's awesome.
If you're an embryo that has had that section of their genome modified, yes. Mutations in hox genes can cause atavisms, such as dolphins with hind fins or humans with tails, although no cases of functional human tails have been recorded.
another fascinating aspect of evo-devo that can easily be seen is the super soldier/worker creation in the ant world. These super ants are created when an unbalance in the colony is seen (usually 95% worker and 5% soldier). The genetic switches that control the evolution of these ants, such as temperature of egg and food source, are performed before the hatch to ensure proper balance in the colony.
For the first question, I believe the idea is that Hox genes are just as susceptible to random mutation as any other gene. The difference is that Hox gene mutations will have an amplified effect on phenotype due to their "Head Architect" type role. If the new phenotype is selected for by nature, evolution takes a dramatic step.
Regarding proteins inherited with the mother egg cell, those proteins and materials are used through the first six divisions of the fertilized egg. Then the Hox genes kick in and build its own things.
The point that the mouse version of the “make-an-eye-here” gene works for flies is amazing. That means that this is a gene that has been in the DNA of these animals’ ancestors, unchanged, since at least as far back as when they had a common ancestor, which is at least (guesstimating here) 300+ million years ago. The fact that it’s the same gene is amazing evidence FOR what creationists deny as “macro evolution”. It makes it obvious that flies and mice have a common ancestor.
McGinnis is a molecular biologist and professor of biology at the University of California, and he studies the evolutionary changes in transcription factors by looking at the Hox genes.
So let's just recap here;
Old genes, like the teeth in the chickens, can be "turned back on".
They had that gene because they evolved from dinosaurs.
Scientists can interact with gene regulators, like putting an extra eye on the fruit fly.
... Do I have to spell it out?
Where the hell is my Dinosaur theme park?
There's an entire series of movies why that's a very bad idea
Just go to an austrich or emu park
Chris Taylor there are birds parks, and birds are dinosaurs
oh, I thought you were leading up to the point that scientists need to put teeth on chickens because that would have been way more interesting.
Don't be so preoccupied with whether you could, that you don't stop to think if you should.
You can't not tell us the story of how that blood got there!
Amazing facts about Hox genes:
1. Sequence analysis showed that the homeodomain of one of the mouse Hox genes differs from Antp gene of drosophila by only one amino acid.
2. Similar mechanisms for segmentation occur in flies and mammals even though they are separated by some 600 million years of evolution.
3. Everything else about hox genes.
1:41
"Shut up"
"No I won't shut up!"
You tell em Hank
I wonder what would happen if we turned on all the regulatory genes in a human, i like to imagine we'd have superpowers but i'm guessing we'd look like something out of a horror movie.
+Ulrich Purath I disagree. I think that humans evolving quickly could be a success to the sustaining of the human race.
+Dragonaut111 Tumor. You would be a tumor.
and messing with the human genome like that is pretty illegal.....
Dragonaut111 GREAT MOVIE IDEA
we would look like cronenberg monsters
Another question: When they did this messed up experiment and the fruit fly grew an eye on it's leg, did they test to see if the fruit fly could see from this new eye? ie did it have an optic nerve connecting to its brain? I assume not, since that would require more instructions to be sent to make the optic nerve also. Fascinating subject, I must know more.
And does that mean that we could maybe eventually create "super beings" that have features that enhance their function? like actual functioning eyes on the back of your head; or lots of mini brains that we have forced to grow inside of your thorax that will enhance your psychological abilities?
@@grinleef295 5 years later, the science is in. Theoretically yes. Though no one has done this on humans for obvious reasons.
@@grinleef295 Oh god! That's like.. If I.. I can't even form this question.
Right, so let's say we somehow make a human with an eyball(s) on the back of it's head, even if it's connected with the brain; how would it see if our brains aren't accustomed to 360 field of view? Or are they?? Would it be a 360deg view with blurred spots near ~160-200deg?
Or would the image overlap in the front if you've got all your eyes open?
Lets not even talk about the eyes on limbs...
There seems to be a contradiction between physics and biology. According to physics, nothing travels faster than the speed of light. However in RUclips comments, creationists have their arguments shot down in flames in what appears to be faster-than-light speed.
*Goes to comments section to see if there's anything interesting.*
"Who else is watching this for their AP class test they have tomorrow?"
*Nope...*
Yamikaiba123 I am watching it for philosophy
what about an IB MYP test?
Curiosity?
I was looking for some insightful discussion but apparently, everyone else is studying for their tests
Im in college our professor just uses these videos instead of lectures. Literally that is it nothing else just a link to the video a discussion about the video and a weekly 25 question test that is word for word pulled from quizlet. 4,000 a semester well spent(sarcasm). Also this is not some low level community college this is a tenured professor at a D-1 school, and people wonder why our generation complains about the education system.
This isn't just regular evolution. This is... _advanced evolution._
I am so glad Hank exists. There needs to be someone to show the proper level of enthusiasm for this stuff.
-astonished- "Shut up!"
-sassy- "No, I will not shut up"
xD
This is absolutely what I want to do with my life. I always have the hardest time trying to explain it to people, now I'll just show them this. I love being a scientist.
As usual it's a great video but the major mistake is listing homeobox and Hox genes as the same things. All Hox genes are homeobox genes, but not all homeobox genes are Hox genes. It isn't just a misuse of brackets, later in the video Hank says we have several hundred Hox genes in our genome, which is entirely wrong. If you Google "difference between Hox and homeobox" it'll be explained.
I love Crash Course!
In my Advanced Biology course at my college, he has us watching your videos every week! Thanks for making such great content!
This guy is truly amazing! I've never thought that someone can combine science and humor and make it really interesting to listen the stuff which is normally boring to read about
i cant entirely blame critics of evolution as i doubt any person is equipped to truly grasp the length of time involved in such a process. and you wouldnt be entirely wrong either to say "its just a theory." but the fact remains that evolution is one of the best supported scientific theories in ever. there are absolutely heaps of evidence to support it and to say something like "call me when you see it happen" is to say: if two men go into an empty room with one door and no windows, one comes out with a hot gun, and the other is found recently dead of a gunshot wound from that same gun, no one can be found guilty since it wasnt observed.
"How about 85% similar?"
*"SHUT UP"*
Liking, just for the "SHUT UP!!" comment in the background.
This video did terrible things for what was a mild fear of birds.
Don't think abput them as Bords, think about them as avian dinosauriers, after all they are closely related to velocyraptors
My cockatoo is just a bird version of a 5 year old. If you hold it she wants it, and if you aren't looking at her she is mad. But give her 5 seconds and she will crawl up into your sweatshirt and cuddle with you.
I don't normally add something to my favorites list, but this video had me fascinated enough just with the potential for new discoveries that I had to do so. Thanks!
I'm not studying any of this for uni and have legitimately no reason for watching this. But god damn it was fascinating.
"Shut up!" "No, i won't shut up"
1:58 xD
BLOOD STAIN ON THE CEILING! Jesus.
"Shut up..!"
"No, I will not shut up"
Haha, hilarious
"Shut up!" Was also my reaction. Hank Sassy reply was not expected. I love this, made my day. #BioLover
This was one of the coolest crash course biology episodes yet! Thanks for the comprehensive overview of such a cool field! The part about chicken teeth made my brain esplode!
This is officially the coolest thing I've ever learned!!
This is my favorite Crash Course video.
Hoemobox genes are something I'm gonna start studying in A-Level Bio soon, so I thought I'd give this a rewatch.
Thank you for making A-Level seem easier!
I love CC but Idk why they say at the end of their videos "if you have any questions ask us in the comments."
I've never seen them in the comments whatsoever
_I have, frequently._
can you point me to where you seen it?
_There are plenty in the newer courses._
Probably to get ideas for future videos
"How about 85% similar?" *background* "Shut up!" *Hank looks backwards* "No, I won't shut up!"
Lol
Funny, the asterisks I put in my comment disappeared.
4571police It's cause of youtube's new google + comment format.
Huh.
Hank et al,
Love your shows! Love 'em! But I am blown away by the amount of (let's call them crazy people) your videos attract, the kind who get offended by science because it doesn't support their religious teachings.
I just wanted to let you know they're not the only ones watching. (What? They're not watching? They're just posting comments? ... oh.)
That's a bit disrespectful, and not really funny.
It amuses me how both:
-Some religious people (particularly monotheists) think they're so right about science (well, evolution) being all a load of tish-tosh.
-Some atheists think they're so right about religion being flat-out wrong, and science being right. And they smugly like to point out that those of the above criteria are ignorant, uninformed and old-fashioned.
Look, perhaps there're faults in both things (i.e. banking solely on religious scripture or scientific evidence). So can't we just be respectful (i.e. omit the "crazy kind" and the prejudices of the so-called 'eager' and 'stupid' religious believers who allegedly skim through scientific videos simply to post comments about science being wrong), and not infuriatingly smug?
We all know the saying: "Pride comes before a fall."
That being said, I agree that this show is awesome.
Have a good day.
As someone in CS, evo-devo makes me very happy! It's kind of like computation is the last major paradigm shift in human understanding. After that, understanding new things becomes a recursive call to that paradigm itself.
When we watched some of these videos in class after taking notes about the topic, I was tripping over his words because he talked too fast. Now that the Bio exam is coming up, I'm binge watching all these videos, and it's absolutely amazing. These videos tie up everything I learned, and I am able to catch up with his pace very quickly since I know everything. I wish luck to those who are taking the Bio Exam in 2017!
Why is this so infrequently mentioned during debates on evolution?
Good point, i think it will be an great argument and also hard to counter too :)
it's new
Who actually googled up Bill McGinnis?
***** ....me.
Lol me too
me
me
Me!
So could you take a "grow a tail here" hox from another animal, put it in a human, and make them grow a tail?
Hackers show more respect for the coders than these guys! Amazing how they can't see the Truth staring them in the face. Too bad that Bush-appointed fed judge OUTLAWED EINSTEIN's views..."I want to know how God created this world. I am not interested in this or that phenomenon, in the spectrum of this or that element. I want to know His thoughts; the rest are details." OR "Every one who is seriously involved in the pursuit of science becomes convinced that a spirit is manifest in the laws of the Universe-a spirit vastly superior to that of man, and one in the face of which we with our modest powers must feel humble." Its good to see they're backtracking on "junk DNA" though...quietly.
I believe they mention (maybe this video or a previous one) that we begin our development with a tail and, I suppose, have genes that say "no tail at this point" for humans. It appears that all the embryos have a little tail when they start developing... and I'm pretty sure there are people that have longer spines that protrude like a tail.
antoinette laforce So.. yes. (: I wonder if it would be unethical since its something that can be removed without causing deformity.
Kendra Desmone I don't know about unethical but I'm sure there wouldn't be too many folks lining up for a tail... or, could be big business for the cosplayers at comicons. Lol! But, yea, we could possibly have tails :)
antoinette laforce Too bad wings aren't possible :( I'd rather have those than a tail
i am a Computer Engineering student(i love science! if you're asking why i am here) and this topic is pretty interesting. Those instructions, those genes triggering a chain reaction is like a computer microprocessor. It is made of bunch of transistors which are basically switches, different configuration of switches will make different logic gates, arrange them and triggering a single switch will trigger other gates and switches in a nanosec chain reaction that will eventually get the work done.
These videos are like TED talks. In that they're educational, entertaining, and awesome.
So technically if cloning doesn't pan out we can still have dinosaurs in our future?? I want a pet Raptor!!
eaglerocks123 we will never have any exact dinosaurs. If we genetically modify a chicken it will be a chickenasaur.
Hi if you don't believe in this, no need to troll. And no need for anyone to get in huge arguments. None of you are going to change anyone else's opinions
No need for you to tell people to stop posting conflicting opinions. And when you say no one will change anyone's opinions, you use the presuming omniscience logical fallacy.
No need for you to tell people there's no need to post conflicting opinions. In fact, there was no need for me to make this comment about there being no need for you to say there was no need.
Dear Crash Course,
Can you easily explain genetic drift?
I've already read about a lot of this a while ago in the book "How to Hatch a Dinosaur", but this video does a great job at summing it all up and making it seem really cool.
I started watching Crash Course in order to pass the final high-school examination. I still use it to revise for the uni exam, but man, I would watch this as a TV show before going to bed!!
Thanks everyone who makes this possible, whether it be for us who need to pass the exams, or us who enjoy geeking out on stuff like this :)
+andrewcapko Or in my case, it's actually PART of my biology homeworl. Biology just got 10x more interesting.
Who would have thought - biology adopted object-oriented programming. :)
More like the other way around. Inheritance was a term in biology long before it was in OOP. Same with polymorphism.
DNAunion It's a rugged, well though-off and effective model with its own detailed terms and concepts that bases itself on the principle that explains the progress of life from basic to complex... would have been a waste not to take it.
You know that software engineers taken a note from nature, look up genetic programming, genetic algorithms and evolutionary algorithms, one can use these heuristics (techniques) to optimise programs and search for solutions to problems. Some, such as NASA, have also be used GA/GP in conjunction with Computer Aided Design to create machinery too.
0:03 watch this in 0.25 times speed
Wait wait wait. So through manipulation of these regulatory genes, you can easily - relatively speaking - control where body parts are positioned. So we could, for example, genetically engineer humans with lots of legs that should actually function as human legs by, say, using a regulatory gene(s) from, say, a spider?
Well, number 1, that would be super unethical, and number 2, legs require a lot of other stuff to work like legs - a pelvis to plug into, a bit of backbone to tie the pelvis into the rest of the skeleton...
In short, you could probably do it, but it would take a lot of very messy experimentation and a knowledge of genetics greater than what we currently know. You couldn't have settled for a 6th digit on the hand, could you?
Absolutely, but I'd like to just point out that you wouldn't need to take the hox genes from a spider to give a human more legs, you could just have multiple iterations of our own hox gene for legs! Like Hank said, the regulatory genes don't actually say anything other than "make leg here" - and lots of animals make legs with the *exact* same regulatory hox gene.
Like mentioned, however, human legs need a pelvis and a pelvis is a pretty complicated structure. We could put lots and lots of legs on somebody but those legs would be very limited in movement and would serve no purpose other than to make life really, really difficult.
You could but it's not as easy as putting them in a fruit fly or something since humans are _waaaaaaaaaaaaaaaaaaay_ more complicated than flies, and no one would want the extra legs, and such
I struggle with all of science and have been watching these videos to try and better myself and i have to say this was definitely interesting, and really thought evoking thanks
Fantascinating...love it. One thing to note is that humans are also sometimes born with prehensile tails, an the snake is born with vestigial legs, or the chicken embryo has vestigial teeth.
Snakes with legs? No thank you.
Boas have remnants of rear legs en.wikipedia.org/wiki/Pelvic_spur
killerbee256
Good ole vestigial traits :)
I could see them tripping all the time.
omg now i understand why birds are considered reptiles
so can we activate all dinosaur genes and then make something as dinosaur resembling as possible. also would that mean that chicken tastes like dinosaur?
Or you could just make a chicken grow a full tail, teeth and fix it's arms. www.creativereview.co.uk/images/uploads/2012/10/convenience_food_1.jpg
www.inspirefusion.com/featherless-chicken/
A really cool thing to do until it eats you
The story about the fruit fly actually made me cry. We still have so much to learn about ourselves.
Fantastic video. These are getting much easier for me to follow now and much more distinctive. Doesn't seem like as much of a mad rush. I understood the earlier videos, but I was never going to retain any of it.
F A N T A C I N A T I N G
Wait does that mean we can make dinosaurs from birds
In theory, yes.
I'm... going to become a biologist? I'm just a curious physicist/chemist/mathematician, pls don't hurt me T_T
BLOODMOONNNNNNNNNNNNNNNNN! *gets out knife*
*swiftly disarms KnightCraft 130* not today scumbag, not today
Bonus points if you know where that quote is from
jokes on you sucker i got like 10 mil knifes *pulls out Knife-seption
KnightCraft 130 I hate to do this, but... *pulls out the mother of all machine guns*
bruh you can't beat Knife-seption it's just not done *pulls out Knife-seption machine gun*
hands down, the best educational channel on youtube!
Yes, you blew my mind! WOW! The beginnings of answers to questions I asked as a kid in school ... so many years ago that your parents might not have been born yet. :-) Not a lot of things make me want to be young again, but evo-devo makes me want to be a little nerd-kidlet again in today's era of scientific discovery. Thanks, Hank.
Damn, Our lord and Savior works in mysterious ways... I PRAY TO YOU EVERY NIGHT FLYING SPAGHETTI MONSTER LET YOUR NOODLEY APPENDAGES BLESS ME WITH HOPE
When you walked in the sand and saw no sets of tracks, that's where the FSM cradled you in his noodley apendages as he hovered along.
"Not gonna lie, they had us in the first part"
Nice to meet u my fellow atheist.
💖
Glad to meet another atheist like me.😘
U got me good with the first part. Lol.
+Charlie Peterson: Um, what? Humans didn't evolve from reptiles, and spiders are not reptiles.
In response to your, "So if you can turn on old regulatory genes that have been repressed through mutation... does that mean humans could redevelop reptilian traits? The Amazing Spiderman all makes sense now."
Reptiles came before mammals. Yes, we evolved from reptiles.
Kronimiciad No, mammals did not evolve from reptiles. There are two clades of amniotes: synapsids and sauropsida. Mammals evolved from the former whereas reptiles evolved from the latter.
DNAunion In other words we were all fish. If I remember correctly, and I am probably wrong, fish evolved into amphibians, then MAMMAL LIKE REPTILES so in a way Kronimiciad was right, but I said they were Mammal like Reptiles.
Hannah Glenn well were did those fish come from.
jacob nichols
en.wikipedia.org/wiki/Pikaia (may be an ancestor of fish, or at least anatomically close to an ancestor of fish)
en.wikipedia.org/wiki/Haikouichthys (may be an early fish)
Took a break from my biochemistry research project in a medical school lab to watch this video! Keep it up!
This was a great episode IMO. Probably the most exciting of the lot. In part, I think the dood's excitement rubbed off on me XD
Chicken growing teeth is super awesome. What a vindication of the theory of evolution.
@crashcourse Thank you everyone who works on these! So awesome!
The best one of the series so far. You made me a fan. Go evo devo!!!
I think this is the first episode that told me something really new. And it was awesome! Don't get me wrong, the others are great, too, to help me not forget all that stuff I read a long time ago...
Keep spreading the awesome, guys!
"Shut up!"
"No, I won't shut up."
Dayuum, the sass is reaaal
To answer the second part of the question, the removal of earlier traits alongside new ones is enough to account for the speed of bird evolution. Additionally, many of those traits were already developing in raptors and their relatives. For example, they had strong legs for jumping. Feathers are first shown from the early Jurassic, millions of years before birds hit the scene.
"Fantastisizing!"
Nice one. As a nursing student who is miserable in microbiology class, I'd like to thank you for making it more exciting, interesting and relevant. Please keep it up.
DFTBA
4:21 Now you don't have to google it: Bill McGinnis is a molecular biologist at the University of California, San Diego. McGinnis studies the evolutionary changes in transcription factors by looking at the Hox genes. His main research has been comparing Hox genes between species to see if they are kept intact during evolution. One long term objective of the research in his lab is to understand the molecular interactions that underlie functional specificity in the Hox patterning system.
fantasinating. you evolved that word to better express evo-devo's awesomeness
thanks so much hank!!!! your videos are the best introductory learning tools! always keeping it interesting and i have to admit i cant help but smiled a few times throughout the video at your nerdiness haha! cheers!
This just saved me about an hour of searching the internet for AP Biology. Thanks Hank
These CraschCourse videos are just brilliant! In behalf of all your fans, thanks a lot, Green brothers!
Homeotic genes also known a homebox genes are not the same as HOX genes as u stated at 2:54. They are different.
A homeobox is a sequence of DNA within a gene. The protein that results from the gene will will include a small number of amino acids that are dictated by the homeobox sequence. This part of the protein is known as the homeobox domain (or just homeodomain).
The importance of the homeodomain is that this is the part of a protein that can interact directly with DNA (or RNA). So, proteins that contain a homeodomain can act as transcription factors. Equivalently, genes that contain a homeobox sequence can be regulatory genes.
Hox genes are simply one group of genes that contain a homeobox sequence, and which are very important in body plan development. However, there are plenty of other genes that are not hox genes and also contain a homeobox sequence.
It's possible for chickens to have teeth?
Sir Hank Green, you have accomplished your goal. You have BLOWN my mind.
"Fantascinating" is now part of my vocabulary. I needed a word to properly express my excitement when learning cool stuff.
+Leah Markum Never watched star trek did you?
Best episode of Crash Course Biology so far. Well done, Hank & Co.
It's always retained in the genome--certain genes just get "turned off" or "inactivated" (and thus the traits get unexpressed) or genes change through mutation. In order to get a new species with new traits, all you need to have is an altered genome. In the case of birds, they happened to get several genes turned off (ones that code for scales, tails, teeth, etc.) while new gene mutations called for the development of wings, beaks, feathers, etc.
There's some dripping water in the background of the video (intentionally). It's not annoying; I just noticed it and thought it was worth pointing out.
Also I'm just as blown away by instantly giving chicken teeth as Hank seemingly was. That's incredible.
This is my favourite CrashCourse Bio video so far! Love your enthusiasm Hank :)
This was the coolest episode so far!
Brilliant stuff! Evo-Devo has been a fascination of mine, ever since i learned of evolutionary biology. Thanks!
I love how Hank said "you PROBABLY haven't thanked your mom" because ya know Nerdfighteria and some people probably have actually thanked their mom for that
Really great video. You did an awesome job of explaining these new ideas and thoughts in biology. Not an easy task, new ideas are so often tumbled and tangled up in such a way that makes it especially difficult to sort, teasing the meaning of them out of them. Thank you very much.
one of the best videos yet! fantascinating
I just watch this for fun, this was a very fun one! Such awesomeness! I watched a programme recently where a guy was looking at chicken embryos, and showing how they could basically make tiny chicken dinosaurs by re-surfacing those old features that begin in the development but aren't kept for hatching.
This is an awesome video! Evolution and mutations are incredible and fascinating. Fantascinating indeed :D
Always nice to see someone who actually knows about the halo universe for a change :D
When I was a kid and I said I wanted to be a scientist, I specified Archaeologist and that I wanted to dig in the ground looking for lost pieces of our past. And I did, I am, and it's awesome.
If you're an embryo that has had that section of their genome modified, yes. Mutations in hox genes can cause atavisms, such as dolphins with hind fins or humans with tails, although no cases of functional human tails have been recorded.
another fascinating aspect of evo-devo that can easily be seen is the super soldier/worker creation in the ant world. These super ants are created when an unbalance in the colony is seen (usually 95% worker and 5% soldier). The genetic switches that control the evolution of these ants, such as temperature of egg and food source, are performed before the hatch to ensure proper balance in the colony.
For once i can honestly say history is more fun... I love Hank but John is my favourite teacher.
Science is absolutely amazing. I can't even express how i feel about it. Thank you so much for you videos
For the first question, I believe the idea is that Hox genes are just as susceptible to random mutation as any other gene. The difference is that Hox gene mutations will have an amplified effect on phenotype due to their "Head Architect" type role. If the new phenotype is selected for by nature, evolution takes a dramatic step.
Regarding proteins inherited with the mother egg cell, those proteins and materials are used through the first six divisions of the fertilized egg. Then the Hox genes kick in and build its own things.
Favorite crash course bio so far. Great job Hank
The point that the mouse version of the “make-an-eye-here” gene works for flies is amazing. That means that this is a gene that has been in the DNA of these animals’ ancestors, unchanged, since at least as far back as when they had a common ancestor, which is at least (guesstimating here) 300+ million years ago. The fact that it’s the same gene is amazing evidence FOR what creationists deny as “macro evolution”. It makes it obvious that flies and mice have a common ancestor.