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Flickr: Eggplant

8 Facts Revealed by Genetic Analysis of the Platypus

Original image
Flickr: Eggplant

You’ve heard the joke: “After God finished making all the animals, He took the leftover parts and made the platypus.” While the platypus does not, in fact, have an actual beaver’s tail nor a duck’s bill, genetic analysis proves that the platypus is confounding well beyond its external mismatched/mish-mashed characteristics.

1. Fur

Mammals are hairy by definition, and platypuses are hairier than most. They waterproof their dense fur by preening it free of oil and schmutz, and the clean fur acts as a sort of dry suit, trapping pockets of air to keep platypuses warm underwater. (Yes, sadly, “platypuses” is the official plural for platypus, though “platypi” is used in the Latin names for some insects. Or maybe you prefer platypodes?)

2. Mammaries

Like all mammals, platypuses nurse their young on milk produced by mammary glands. Thanks to 2008’s Platypus Genome Project, we know that platypus genes that are responsible for milk production read a lot like the milk-making genes in other mammals, humans included. Scientists now think that mammals have been producing milk for over 166 million years, which would mean milk production has been an instrumental evolutionary rudder in the development of modern mammals. Haha: udder rudder. Except...

The platypus doesn’t have teats. Instead, it oozes milk from mammary “patches,” which are kind of like areolae without the nipples. Other animals that nurse via mammary patches? Oh, just the four species of echidna (spiny anteaters), which, together with the platypus, make up the entire order Monotremata, also known as “egg-laying mammals.”

3. Eggs

Platypuses lay leathery, reptile-like eggs, but their genes tell us that their egg-making genes are more mammalian—in some ways. Other egg-related gene characteristics are shared with birds, amphibians and fish, while still others are only shared with birds and fish, and those genetic traits only partially shared.

Much like marsupials (kangaroos, possums, and other pocketed animals), platypus young are born (i.e. hatch from their leathery eggs) in a semi-fetal state, and continue developing throughout the nursing process. In fact, echidnas keep their young in a pouch after hatching; platypuses instead dig deep, complex burrows in which to safely build their nests. How?

4. Feet

...With their clawed feet, which are also webbed for swimming. Who says working moms can’t have it all?

5. Eyes

The platypus’ eyes alone have been the subject of much publication, possessing (again) a mosaic of characteristics found in disparate animal orders. For instance, they have a rod/cone balance that most closely resembles that of other mammals, but also have a “double cone” thing going on, a feature not found in eutherian mammals (mammals that give birth to fully developed young) or marsupials. Meanwhile, their eyeballs are enclosed by a type of cartilage more like that seen in birds, reptiles, amphibians, sharks, rays, and lungfish.

6. Poison!

Male platypuses have pretty mean built-in weapons: spurs on their hind legs that are loaded with a venom potent enough to kill a dog and debilitate a human for days. While there are a few other types of venomous mammal out there, this type of venomous sting could be considered a more reptilian-like trait; that is, the venom itself is made up of organic material similar to the venom in reptiles. However, according to the platypus genome, that organic material gets made via variations in different genes than in reptiles. Reptilian result, uniquely platypusal cause.

7. Sexy bits

The sex of the platypus is determined by a set of ten chromosomes, which, according to platypus geneticist Jennifer Graves, “are absolutely, completely different from all other mammals. We had not expected that.” Each platypus sperm contains either all X or all Y chromosomes. And the platypus X chromosome looks more like the Z sex chromosome that shows up in birds.

8. Electro-sensory system

In case you weren’t yet convinced that the platypus is “special”: It hunts via a system called electroreception, which is exactly as rad as it sounds. The skin in its bill is highly sensitive, and its combination of touch receptors and electroreceptors (comparable to those found in electric fish) pick up on movements and low-frequency electrical signals in its prey. That’s why, even hunting underwater, at night, the platypus can still bring home the bacon. It’s like, guys—leave some cool stuff for the rest of us, maybe.

Primary image via Flickr user The Eggplant. 

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iStock // Ekaterina Minaeva
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technology
Man Buys Two Metric Tons of LEGO Bricks; Sorts Them Via Machine Learning
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iStock // Ekaterina Minaeva

Jacques Mattheij made a small, but awesome, mistake. He went on eBay one evening and bid on a bunch of bulk LEGO brick auctions, then went to sleep. Upon waking, he discovered that he was the high bidder on many, and was now the proud owner of two tons of LEGO bricks. (This is about 4400 pounds.) He wrote, "[L]esson 1: if you win almost all bids you are bidding too high."

Mattheij had noticed that bulk, unsorted bricks sell for something like €10/kilogram, whereas sets are roughly €40/kg and rare parts go for up to €100/kg. Much of the value of the bricks is in their sorting. If he could reduce the entropy of these bins of unsorted bricks, he could make a tidy profit. While many people do this work by hand, the problem is enormous—just the kind of challenge for a computer. Mattheij writes:

There are 38000+ shapes and there are 100+ possible shades of color (you can roughly tell how old someone is by asking them what lego colors they remember from their youth).

In the following months, Mattheij built a proof-of-concept sorting system using, of course, LEGO. He broke the problem down into a series of sub-problems (including "feeding LEGO reliably from a hopper is surprisingly hard," one of those facts of nature that will stymie even the best system design). After tinkering with the prototype at length, he expanded the system to a surprisingly complex system of conveyer belts (powered by a home treadmill), various pieces of cabinetry, and "copious quantities of crazy glue."

Here's a video showing the current system running at low speed:

The key part of the system was running the bricks past a camera paired with a computer running a neural net-based image classifier. That allows the computer (when sufficiently trained on brick images) to recognize bricks and thus categorize them by color, shape, or other parameters. Remember that as bricks pass by, they can be in any orientation, can be dirty, can even be stuck to other pieces. So having a flexible software system is key to recognizing—in a fraction of a second—what a given brick is, in order to sort it out. When a match is found, a jet of compressed air pops the piece off the conveyer belt and into a waiting bin.

After much experimentation, Mattheij rewrote the software (several times in fact) to accomplish a variety of basic tasks. At its core, the system takes images from a webcam and feeds them to a neural network to do the classification. Of course, the neural net needs to be "trained" by showing it lots of images, and telling it what those images represent. Mattheij's breakthrough was allowing the machine to effectively train itself, with guidance: Running pieces through allows the system to take its own photos, make a guess, and build on that guess. As long as Mattheij corrects the incorrect guesses, he ends up with a decent (and self-reinforcing) corpus of training data. As the machine continues running, it can rack up more training, allowing it to recognize a broad variety of pieces on the fly.

Here's another video, focusing on how the pieces move on conveyer belts (running at slow speed so puny humans can follow). You can also see the air jets in action:

In an email interview, Mattheij told Mental Floss that the system currently sorts LEGO bricks into more than 50 categories. It can also be run in a color-sorting mode to bin the parts across 12 color groups. (Thus at present you'd likely do a two-pass sort on the bricks: once for shape, then a separate pass for color.) He continues to refine the system, with a focus on making its recognition abilities faster. At some point down the line, he plans to make the software portion open source. You're on your own as far as building conveyer belts, bins, and so forth.

Check out Mattheij's writeup in two parts for more information. It starts with an overview of the story, followed up with a deep dive on the software. He's also tweeting about the project (among other things). And if you look around a bit, you'll find bulk LEGO brick auctions online—it's definitely a thing!

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iStock
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Health
One Bite From This Tick Can Make You Allergic to Meat
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iStock

We like to believe that there’s no such thing as a bad organism, that every creature must have its place in the world. But ticks are really making that difficult. As if Lyme disease wasn't bad enough, scientists say some ticks carry a pathogen that causes a sudden and dangerous allergy to meat. Yes, meat.

The Lone Star tick (Amblyomma americanum) mostly looks like your average tick, with a tiny head and a big fat behind, except the adult female has a Texas-shaped spot on its back—thus the name.

Unlike other American ticks, the Lone Star feeds on humans at every stage of its life cycle. Even the larvae want our blood. You can’t get Lyme disease from the Lone Star tick, but you can get something even more mysterious: the inability to safely consume a bacon cheeseburger.

"The weird thing about [this reaction] is it can occur within three to 10 or 12 hours, so patients have no idea what prompted their allergic reactions," allergist Ronald Saff, of the Florida State University College of Medicine, told Business Insider.

What prompted them was STARI, or southern tick-associated rash illness. People with STARI may develop a circular rash like the one commonly seen in Lyme disease. They may feel achy, fatigued, and fevered. And their next meal could make them very, very sick.

Saff now sees at least one patient per week with STARI and a sensitivity to galactose-alpha-1, 3-galactose—more commonly known as alpha-gal—a sugar molecule found in mammal tissue like pork, beef, and lamb. Several hours after eating, patients’ immune systems overreact to alpha-gal, with symptoms ranging from an itchy rash to throat swelling.

Even worse, the more times a person is bitten, the more likely it becomes that they will develop this dangerous allergy.

The tick’s range currently covers the southern, eastern, and south-central U.S., but even that is changing. "We expect with warming temperatures, the tick is going to slowly make its way northward and westward and cause more problems than they're already causing," Saff said. We've already seen that occur with the deer ticks that cause Lyme disease, and 2017 is projected to be an especially bad year.

There’s so much we don’t understand about alpha-gal sensitivity. Scientists don’t know why it happens, how to treat it, or if it's permanent. All they can do is advise us to be vigilant and follow basic tick-avoidance practices.

[h/t Business Insider]

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