A Worm That Can Be Cut In Half!

June 22, 2025

You may have heard that one rumor about cutting earthworms in half. That, if you split ‘em straight down the middle, they’ll grow into two new earthworms?

Yeah…that’s just a myth. Please don’t do this.

Earthworms can regenerate their tail end if it’s cut off, but they still won’t regenerate into two separate worms. Damage from the clitellum (that larger segment in the middle) and above will kill the worm.

That said, while earthworms can’t be split into two separate worms, that doesn’t mean we the rumor is 100% false! There’s a kernel of truth to it…we’re just looking at the wrong worm. We need to turn our attention towards these little guys: an order of flatworms known as Tricladida…or more commonly, planarians.

Many flatworms are parasitic, but planarians are among the kinds that aren’t! Some of ‘em are even quite cute, with little rudimentary eyes and an adorably squooshy body. But that isn’t the only cool thing about them. They have amazing regenerative abilities, like recover-from-the-tiniest-fraction-of-their-bodies level. And yest, if split right down the middle, they’ll regenerate into two new li’l guys.

One more thing: if a planarian is only partially split, it’s possible for you to get one with two heads, as each half regenerates its own head! Kinda makes me wonder how their digestive system works in that case. Do they share a single digestive system? Considering how planarian digestive systems work, that could have some weird ramifications. Normal planarians don’t have an anus, they just have a single “blind sac” that both takes food in and excretes waste. So…the worst case scenario for our two-headed friends is…

…Probably best not to think about it.

What's New In Science: Peanut Allergies

June 12, 2025

There has been a fascinating study on peanut allergies published in Science Translational Magazine this month, and it could have huge significance towards our understanding of how we develop allergies in the first place. But in order to understand all that good stuff, here’s what you’ll need to know about antibodies:

Antibodies are molecules produced by a type of white blood cells known as B cells.

All B cells are the same at first, and share the same basic DNA (“germline sequences”, if you’re feeling fancy). When B cells begin to mature, that B cell’s DNA rearranges itself. Because of that rearrangement of DNA, the antibodies that B cell (and its “kids”) produces will be completely unique to the antibodies other B cells produce. That antibody will randomly have an affinity to a very, very specific random particle, called an antigen. B cells aren’t big believers in being a “Jack of All Trades”.

When that antigen is a viral particle, everything is just dandy. The immune system is working as intended.

When that antigen is a particle found in peanuts…then you have a problem.

Which brings us to the study in question.

The researchers looked into different antibodies that all reacted to the same common peanut antigen. Despite having completely random DNA rearrangements, the B cells all came to the same conclusion: “PEANUTS MUST DIE!!!!”. And now their respective humans need to carry an Epi-Pen for the rest of their lives.

So, our researchers, Marini-Rapaport et al, asked the obvious question: what the HECK is going on with those DNA rearrangements to make peanut allergies so danged common?

First, they identified exactly what parts of the antigen the antibodies all interacted with. They found that the DNA that codes for those interactions was found in base DNA, pre-rearrangement. That makes it more likely that, when recombination occurs, the peanut-binding portion remains.

In other words, peanut allergy isn’t just a purely random thing: our deck is metaphorically stacked against peanuts for some unknown reason! For all we know, ancient peanuts could have had a heck of a kick, for human evolution to see it and go “yeah, I’d rather die than eat THAT again”.

White Blood Cells as Pokémon

June 12, 2025

Something I loved about white blood cells as a kid was how similar to Pokémon they can be. They come in different types, can “evolve”, and even have special moves and abilities they use! Just for fun, here are the five major “species” of white blood cells, reimagined as Pokémon: