In honor of today’s Boston Marathon, and in remembrance of last year’s, check out all the amazing evolutionary adaptations and biological wonders that let us run marathons: The Science of Marathons!
Tripedal to the Metal
That’s some loco motion, huh? Found this neat little GIF showing how an ant’s legs move at a full gallop. While calmly strolling though the picnic grounds, ants have five of their six legs at a time in contact with the ground. But when it’s time to put the (tiny) pedal to the metal, they change their gait to this alternating tripod motion.
This pattern isn’t controlled by the insect’s brain, but rather by bundles of neurons in the leg called central pattern generators. While moving at such a clip, it just so happens that three legs is the minimum number it needs on the ground at a time to balance its rigid exoskeleton without toppling over.
Is that part of the reason that insects have six legs and not another number like four or eight? Or did the gait evolve to match the hardware? My guess is the latter, but I am not sure. What say you, insect folks?
(GIF via NC State University)
My favorite silly gene names
On the heels of this post detailing the adorable story of the hedgehog gene, here’s some more of my favorite silly gene names, and the mutant reasons their redonkulous names:
- tinman - Mutants do not develop a heart (Fruit fly)
- dreadlocks - Causes photoreceptors to sprout dreadlock-like axon projections (Fruit fly)
- tribbles - Causes out of control cell division (Fruit fly)
- maggie - Larvae never mature (Fruit fly)
- hamlet - Affects a type of sensory cell called “IIB” (Fruit fly)
- dunce - Affects learning and memory (Fruit fly)
- smaug - Represses Nanos, which means “dwarf” (Fruit fly)
- groucho - Excessive bristles on the face (Fruit fly)
- ken and barbie - Lack of external genitalia (Fruit fly)
- indy - Stands for “I’m not dead yet”, a la Monty Python (Fruit fly)
- lush and cheap date - Affect alcohol metabolism (Fruit fly)
- RING - A protein segment that comes from “really interesting new gene”
- tigger and pogo - Two families of transposable elements, or pieces of DNA that can jump around genomes (Multiple species)
- kryptonite and superman - Kryptonite represses superman, which causes extra stamens to form in flowers (Arabadopsis)
- Yuri gagarin - Protein involved in sensing gravity (Fruit fly)
- callipyge - Leads to formation of large, round buttocks in sheep (from Greek for “beautiful buttocks”)
- chablis, frascati, merlot, retsina, riesling, cabernet, grenache, chardonnay, chianti, pinotage, sauternes, weissherbst, zinfandel - A set of genes found to inhibit blood cell formation. Get it? Red and white?! (Zebrafish)
I think these would make an excellent art project, all you artistically-and-scientifically inclined people out there. Any of your favorites that I missed?
How The hedgehog Got Its Name
This week’s episode of It’s Okay To Be Smart (below) focuses on a very special chunk of DNA and the things that it does, part of a family of genes that help sculpt complex body shapes across the animal kingdom, from fruit flies to fish to humans to hedgehogs. Sonic hedgehogs, to be exact.
Sonic hedgehog is a gene that every vertebrate carries that, working in beautiful concert with dozens of other developmental genes, helps guide and shape everything from your spinal cord to your face (as Emily showed us in the recent Two-Faced Calf episodes on The Brain Scoop). It helps the developing embryo determine which is the front side of the hand and which is the rear. And coolest of all, it helps precisely five fingers sprout, not four, not six, and determines which will be the thumb and which will be the pinky.
It also has something to do with the evolutionary biology of The Simpsons, but we’ll have to save that for another post.
Sonic hedgehog isn’t the only hedgehog gene we carry. We also carry inside our DNA an indian hedgehog and desert hedgehog. So what’s up with the names? Our array of hedgehogs (that’s the official term for a group of hedgehogs, as it happens) are all related to a gene from fruit flies.
In the late 1970’s Christiane Nüsslein-Volhard and Eric Wieschaus randomly mutated fruit flies and (quite literally) combed through them by the tens of thousands looking for interestingly deformed mutant embryos. Pretty macabre stuff, if it wasn’t flies, eh? Based on this screen (which won them the Nobel Prize), they discovered a swarm of genes that affect how the fly’s body decodes its form (read their original paper). And they gave those genes funny names based on funny patterns or phenotypes in the mutant embryos.
Why? Well, it’s possible that Germans have some hidden sense of humor that they aren’t telling the rest of the world about, but it’s more likely that they named the genes this way because that’s how Thomas Hunt Morgan, master of mutant flies, did it.
How do you get a hedgehog from a fruit fly? Let’s start with a normal fly embryo. Usually these tiny worm-beasts display an elegant, banded pattern of “denticles”:
Well, one of the random mutations that Christiane and Eric identified resulted in a scrunched up embryo with completely bunched denticles. The reasons for that scrunchiness are complex, but if you want to know more, read up on the treasures that lie within pair-rule genes and gap genes. Anyway, since fruit fly folks name genes based on what the mutant looks like (e.g. wingless, yellow, curly) they named it hedgehog!!
Relatives of that gene in other animals were discovered in the following years in many other species, and thanks to the finely tuned comedic skills (and long nights at the pub) that biologists are known for, we ended up with Indian, Desert, Sonic, and in fish, even Tiggywinkle hedgehogs. And that hedgehog lives in every cell, brought out of its burrow with careful genetic choreography to make you the thumbed wonder you are today. Ain’t biology adorable?
What does a 375 million-year-old fish have to do with Sonic the Hedgehog?
I’ll give you a hint: It has to do with the evolution of thumbs! To know the rest, you’ll have to watch this week’s It’s Okay To Be Smart. Do it. Do it now.
Joining me this week is none other than Dr. Neil Shubin, discoverer of the famous Tiktaalik fossil. He’s got a three-part series called Your Inner Fish premiering this Wednesday at 10 PM Eastern on PBS. It’s basically just like this video, only with fewer Sega Genesis references and more Arctic paleontology expeditions.
I’m 100% not sorry for all the thumb puns this week :)
If you could visit anywhere in the universe, in time and space, to witness something wonderful and scientific, where/when would you go?
That’s one of the questions I answered in this week’s Ask Joe video:
My answer? I’d go back to the single day, approximately 2 billion years ago when one cell gulped up another one, and instead of eating it, created the mitochondrion. Our little cellular energy factory, formerly a free-living organism, is the key to the evolution of quite literally all complex life on Earth, plant or animal. As Ed Yong writes in his history of the mighty mito, it happened only once. I’d just want to watch it happen under a microscope, so I could say “Yep, that’s why I’m here.”
Oh man. But what if I sneezed or something? I could ruin the whole universe. On second thought …
Ask Joe #3
This week’s It’s Okay To Be Smart features more soothing knowledge ointment for your burning sciencey questions. You’ll learn about vomit, if bananas and humans share DNA, what the heck “LUCA” means, why “c” is the speed limit of the universe, and what I think was the most important event in the history of life on Earth. Oh, and I share an inspirational message that I wish had made it on the Voyager Golden Record. Ah… if only.
Thanks to everyone who sent in questions! Have a question? You can always send them to me here on Tumblr, catch me on Twitter (use the hashtag #AskJoe), leave a comment on the video page, or that good ol’ email business: itsokaytobesmart at gmail.com.
And how about those banana puns? Right?!
Let This Awesome Science Infect Your Mind
Ed Yong is one of the finest science writers in the world. His National Geographic blog is chock full of the weird, wild, and WTF-inducing stories that make our living world so darn interesting. So I was overjoyed when I heard he would be speaking at this year’s TED.
He didn’t disappoint. In his talk above, he unlocks the under-appreciated and often cringe-worthy world of mind-controlling parasites. They get no respect, I tell ya, no respect at all. Yet they are cornerstones of countless ecosystems, determining food availability and managing population sizes like armies of freaky fauna, each deployed in a Trojan Horse of evolution’s design. Every parasite’s life is a story, by definition, an elaborate chain that extends from host to host, and I think they’ve found their minstrel in Ed. I mean that as a compliment, of course.
Listen to him weave a tapestry of tapeworms, explain what makes flamingos munch on zombie shrimp, show you how a cricket is like a TARDIS, how a wasp turns a cockroach into a cocker spaniel, and how a brain-controlling protozoan reminds him of an Elizabeth Gilbert novel. My favorite part of this? The idea that ideas themselves may be parasites.
I haven’t loved a TED talk this much in a long time. Or maybe that’s just the parasite talking.
Packed Like Protein Sardines
A couple weeks ago I gave you a quick and dirty lesson in how cells are not the neatly ordered bags of water that textbooks make them out to be. Now Harvard’s BioVisions and XVIVO animation bring us this amazing look at the crowded protein pandemonium inside every bit of you.
It’s kind of overwhelming, with all that Brownian twitching and enzymatic oscillation, eh? So overwhelming, in fact, that the only structures I could recognize by sight were the
myosin V walking down an actin filament kinesin on a microtubule walking like a drunk with a shaky step, and some clathrin cages vibrating themselves in and out of vesicle formation. Recognize anything else?
Even if you have zero idea what’s going on, this is a beautiful look at a world beyond sight, informed by decades of study in protein structures and biophysics, and translated into a beautiful combination of sights and sounds. Enjoy this scientific journey!
If you were to flip through the photo album that is your evolutionary family tree, one ancestor after another, all the way back to your great-great-great-great-(etc.)-grandfish… where would the first human show up?
Guess what? There was no first human.
Wait, wut… did he just break evolution? Has Joe gone crazy? Did he fall on his head? Has his brain been taken over by mind-controlling parasites? Why is he saying these things?
Don’t worry. I’m fine, and so is evolution. The video explains everything :)