Q:Is congenital myotonia found in non-domesticated animals?
This question comes from my video about GOATS! so you should watch that first to get an intro on fainting goats (congenital myotonia) and also just because goat science is awesome.
I just spent half an hour digging through scientific literature trying to find reports of congenital myotonia (“fainting syndrome”) in a wild animal and came up with exactly zilch, zero, and nada. We see it in goats, horses, dogs, cats, people… all of which are domesticated species (except for maybe people), but no reported cases in wild animals. Does that mean it’s impossible?
First let me summarize what should happen in a normal skeletal muscle contraction, then I’ll answer that question.
Muscle cells, like nerve cells, actively maintain different concentrations of ions on either side of their membrane. This resting membrane potential is super-interesting, but also pretty complicated, so instead of me turning this answer into a textbook chapter, all you need to remember right now is that the inside of a muscle cell is slightly negative compared to the outside. The ions we need to keep in mind right now are sodium (Na+, higher conc. outside), potassium (K+, higher concentration inside), and chloride (Cl-, higher concentration outside).
When a nerve impulse reaches a muscle fiber, the neurotransmitter acetylcholine opens a sodium-specific door on the muscle and lets some Na+ ions inside.
Sodium is a positive ion, so it makes the inside of the muscle more positive. Then that initial burst of Na+ leads to an even larger Na+ wave. Positivity breeds positivity, people!
This burst of positive charge into the muscle cell is essentially what makes it contract (although I’m leaving out a bunch of stuff, like how calcium comes into play, to dig into more detail on all this, check out these great illustrations from MDA.org)
Of course, muscles don’t usually stay contracted, unless you’re dead, diseased, or get a cramp. Why not? After a short amount of time, potassium ions flow out of the cell through their own special potassium doors (making the inside more negative again) and chloride ions move in through their special chloride doors (making the inside even more negative).
It’s the return to that original inside-negative state that makes the muscle relax (now maybe you can start to see why loss of salt/electrolytes can lead to cramps?)
Finally we come to the fainting goats. Congenital myotonia leads to a mutation in that chloride channel I mentioned up there (if you’re into gene and protein names, it’s called CLCN1), meaning that those muscle cells take longer to return to their normal negative-on-the-inside charge and stay locked in the “on” state.
That’s what we see in “fainting” goats, or any other creature with congenital myotonia. The muscles just lock up, and the “fainting” is really just “falling over thanks to suddenly obtaining the flexibility of a statue.”
So does this mutation exist in wild animals? Probably. There’s no reason a wild animal could gain a spontaneous mutation in its chloride channel gene and have particularly rigid offspring. Only these statue-creatures would be easy pickings for predators, as in “easiest meal evar,” and that mutation wouldn’t be able spread throughout the population. Since we can’t keep track of every single wild animal and their offspring, we probably never see it (although there might be isolated reports out there). Like, what’s happening with this panda? I don’t even know.
On the other hand, we inbreed the hell out of domesticated animals, and thanks to fences, sharp sticks, and sheepdogs, we tend to keep them fairly safe from predators (not to mention that humans don’t have any predators except each other). So whether or not they have the genetic misfortune of crumpling into a heap of myotonic hilarity every time we sneak up behind them, we’ve artificially (and accidentally) amplified this mutation in domesticated breeds (although breeders are often encouraged to not breed “fainting” animals).
So the answer to your question is almost certainly yes, although the Bad Wolves keep the Weeping Angels from taking over.
You guys like Doctor Who references?
I worked a couple of ‘em into tomorrow’s episode of It’s Okay To Be Smart. Why did I do it?
And because I’m…
I kinda got the whole idea to do the video from Amy Pond.
Yeah, it’s gonna be pretty cool.
I can’t, that would spoil it. You’re just gonna have to wait until the video is up.
That’s not very nice. Just be patient.
Apology accepted. So you gonna watch tomorrow’s video?
Science fans and book lovers! I’ve got a special challenge for you…
I’m teaming up with the amazing book project Call me Ishmael for the first of what we’re calling an “All Call Challenge"…
What does that mean? We want YOU to tell a story of a book that changed the way you look at the natural world. You can hear the full details on the challenge, plus hear a book-themed interview with me by clicking here, or by checking out the video below:
I’m betting you smart people are full of amazing stories about amazing stories. Remember, if you do submit your story to Call Me ishmael, make sure to say that you’re answering the It’s Okay To Be Smart “All Call” challenge! I predict a few more of your favorite YouTubers will be issuing “All Calls” in the near future, too.
A few of you figured it out already, but I answered my own challenge yesterday, in this “anonymous” Call Me Ishmael submission:
Help us spread the word, stay curious, and keep on reading!
#7: Chernobyl Joe
Pruney Fingers: A Gripping Story
In this week’s special "Summer Science" edition of It’s Okay To Be Smart (which you have already watched, right?!), we took a quick look at why our fingers wrinkle up when we’ve been in the water for a while.
While scientists used to believe this odd occurrence was just our skin getting soggy, but that explanation doesn’t hold water. Besides, if that was the case, why does this only happen in our fingers?
Modern science has added a wrinkle to this tale. Biologists noticed that if the nerves that fed into the fingers were damaged or severed, then the skin no longer got pruney. This means that some sort of active process is driving the prunification, a very (un)conscious decision on the part of our brain and body.
Could it be that pruney fingers are an adaptation? An odd phenomenon that actually gives us an advantage in wet conditions? It’s still not known for sure, but judging by the work of neuroscientist Mark Changizi it seems likely.
In the above video from TED-Ed, Changizi explains how, if we predict that wrinkly fingers act like dermal tire treads, we should see the same patterns in our skin that we see in river drainage networks. It turns out that is exactly what we see!
Other scientists went on to test whether those wrinkles gave people better grip under wet conditions. Want to know what they found? Watch the video and soak up some awesome science.
If you haven’t watched this week’s summer-themed OKTBS, you can check it out below :)
*I should note that not everyone agrees with the rain tread hypothesis for pruney fingers, but it’s the best explanation we have so far
This week It’s Okay to be Smart and BrainCraft have teamed up to teach us about our brains!
Check out this week’s It’s Okay To Be Smart!!!
I teamed up with the awesome neuroscience channel BrainCraft this week to bring you two awesome brain stories!! And while you’re at it, enjoy these GIF(t)s!
When you think about it, consuming the milk of other animals is a freakin’ weird thing to do. Curdling, flavoring, and aging it in order to make cheese? That’s even weirder. But cheese is delicious, so whether it’s weird or not I have no intention of stopping. How exactly does milk magically morph from liquid to solid?
The origin of cheese, as the legend goes, can be traced to one (un)lucky Middle Eastern shepherd, maybe as far back as 8000 BCE. Journeying across the arid plains and lacking a container to carry his milk in, this shepherd fashioned a canteen out of the stomach of one of his sheep. Later, when he went to take a sip of milk, all he found was curds… the chunky precursor to cheese.
To this day, the cheesemaking process begins in pretty much the same way as it did in 8000 BCE, only instead of relying on offal accidents, we employ some nifty biochemistry.
To begin its leap toward immortality, milk first has to make the leap out of a cow, sheep, goat, or other grazing animal. Compared to human milk, the milk of these domesticated ruminants is extremely high in protein. For reasons that will become clear shortly, the low protein content of human breast milk is why you can’t make it into cheese, should you be so inclined (although I sincerely hope you are not so inclined).
The reason that milk curdles in ruminant stomachs is because of baby ruminants. Behold the four-chambered ruminant stomach:
When a cow drinks water, or when grazing on hard-to-digest grasses, they engage all four stomachs, but the microbes that live in the top three chambers would create a dangerously unbelchable amount of gas if they were allowed to drink milk. When suckling, calves instead engage a valve that sends the milk directly to the last of their four stomachs, the abomasum.
It is there that the sugar-, fat-, and protein-laden milk curdles, which our friend the shepherd found out the hard way when he used the abomasum for a canteen. Curdling is good for the calf, because as any parent of a newborn will tell you, milk has a tendency to go right through a baby’s digestive system, if you catch my dirty-diaper-drift. Solid milk curds take longer to pass through the digestive system, so more nutrients can be extracted from the milk.
Milk’s main protein, making up more than 80% of the total, is called casein. One particular form of this protein, kappa-casein, is basically the reason that cheese exists at all. Thank you, K-casein, we owe you big-time.
K-casein isn’t very happy floating around in the aqueous environment of milk, though. Like a shark-attack survivor, it’s a bit hydrophobic. In order to hide from H2O, casein molecules huddle together in globs called micelles, binding up fat and calcium along with it.
You’ll notice that casein is more than just the globby bits, though. Its tail (a “casein point”?), coated with sugars and hydrophilic amino acids, juts out from those micelles, caging the protein in a water-loving coat and keeping your milk from becoming a curdled mess… that is, until rennet comes along.
Rennet, the mixture of enzymes added to cheese cultures to start the curdling process, was originally extracted from the stomach linings of young calves, although today it’s manufactured by genetically engineered microbes. One of those enzymes, chymosin, is what does the curdling in both calf stomachs and cheese houses.
Chymosin acts like a molecular pair of scissors, snipping off the water-loving tail of K-casein at a very specific spot (between amino acid 105, a phenylalanine, and 106, a methionine, if you’re a sucker for detail). Without that cage to keep the micelles dissolved in milk’s watery environment, the micelles clump together in massive knots called curds.
What happens to those curds next is an adventure all its own, and every type of cheese has its own well-aged story.
Whether or not the legend of the shepherd is true or just a cheesy myth, one thing is for certain: When it comes to cheese, the stomach isn’t just where cheese ends its journey, it’s also where it begins.
This post accompanies this week’s episode of It’s Okay To Be Smart on YouTube: The Science of Cheese! Watch it here to learn more about cheese-ology:
This is pretty cheesy
I’m sure you havarti watched this week’s It’s Okay To Be Smart all about the science of cheese, but in queso you haven’t, you’d cheddar click here so you can start your journey to becoming a cheese whiz. It’s whey interesting, and covers the basic chemical processes that have o’curd since 8000 BCE, when, as Clifton Fadiman says, milk first took its (accidental) leap toward cheesy immortality in a shepherd’s milk canteen.
You might dis a brie, but I think the microbial and chemical magic that conjures up our favorite cheeses is one of the gratest accidents in human history. It’s aged from “whoops, I ruined the milk” to “edible art form.”
There’s too much cool science in the cheesemaking process for my one video to provolone, so I’ll be writing up some meaux tidbits here on the blog this week. Here’s what I’ve got in store for ya:
- The incredible chemistry of turning milk to curds
- Why does cheese melt?
- Some of the smelly aromatic magic that creates “eau de fromage”
- Why swiss cheese has holes
- Can we make cheese from human milk?
These puns are so edam bad they’re probably making you go emmental, huh? I know you’re feta up and camembert another, but please don’t feel bleu. It’s nacho fault I’m a muenster, it just feels so gouda can’t help it. I can hear you praying to cheezus that it stops soon.
Anyway, if there’s something about the science of cheese you’d like to know, leave it below! What else do you want to learn about quesology?
By Adrián Maldonado
Try not to think about it too much, but we have reached the stage where anyone of college age or younger has lived in an era of the Internet and 16-bit-and-above game consoles. One can only imagine the very strange sort of mid-life crisis people of my generation…
This is a really, really awesome follow-up article in response to my video this week. You should read it.
It’s always a nice feeling when something you make inspires somebody to take the time to create something of their own, but its even better when that new thing takes your original ideas in directions that you never imagined!
For those of us old enough to have done it, the act of blowing on our NES cartridges may represent an emergent behavior that is based on our common interaction with things. Just like shaking Polaroid pictures may just be a natural result of their particular shape and design and that they have an easily shakable thingness, perhaps we haven’t thought enough about how we interact with the physical elements of gaming systems and gaming culture? This article is a seriously cool take on modern archaeology.