Your Brain May Have Started as Two Organs

[u/TheMuseumOfScience]

Your brain may have once been two separate organs! 🧠

Scientists long thought the whole brain grew from a single group of embryonic cells. But a new study of mouse embryos found it actually develops from two, one forming the forebrain and the other the hindbrain. Similar trends in chickens and zebrafish suggest that over 500 million years ago, evolution may have brought two separate nervous systems together to form the brain.

[u/_enigmay]

I've always thought the hindbrain is evolutionary older and the forebrain is a newer addition. Is that true?

[u/BeardySam]

I thought this is pretty much known evolutionary science? They’ve found the gene that causes it which is cool, but this video seems more like “journalist learned a thing” than what the research is about 

[u/Delvog]

"Two groups of cells" does not mean "two nervous systems". Two groups of cells can be parts of the only nervous system, such as ganglia.

[u/MaiLittlePwny → u/Delvog]

Also it runs into the usual Biological concept problem. It's a breakdown of definition to define a thing in the world.

At what exact point do two parts of the same system, that are completely interconnected, and completely dependent on each other parts become two different and distinct systems/organs.

As usual we want clear distinct categories, and biology as ever is simply uninterested.

Even the most evidenced theory in all of human history (Evolution/Origin of Species) falls apart when it relies on identifying distinct species in insects, and a lot of plants. Which are two of the more dominant biospheres.

I think the accuracy of this "new finding" depends almost exclusively on your fondness of semantics and sensationalising info. Otherwise it's a slightly earlier branching in the embryonic cell development.

[u/444cml]

This really seems like a misunderstanding of what composite organs are and what the original paper has said.

For the brain to be two organs, you’d be making the same argument about both the heart and the uterus.

The actual quote from the paper is

We suggest further complexity: although the brain is often construed as a single organ, the brain may itself derive from two parallel progenitors that emerge early in development and that, respectively, form the forebrain/midbrain versus the hindbrain. Analogously, the heart derives from two parallel progenitors, the first and second heart fields, which converge to form a single organ71.

Loh said this in an interview: Having the brain as one organ would probably be more efficient, but we rely on this primordial way to make the brain as two separate pieces

The lead author Jokhai also said this in the same article/interview series: I was surprised at our findings because the word ‘brain’ implies a contiguous organ that likely has a singular origin,* *and “But even 500 million years ago, there were these separate neural systems, which now almost operate as one, which is very cool”

The both authors mistaking “neuron” with “organ” and “brain” in this interview. Organs are by definition composed of multiple tissue types. You would not expect a singular origin for all the cells in an organ. You might however, predict a singular origin for all of a cell type (like neurons) that we’ve classed with the same name. This is why the actual publication explicitly says that the brain develops into a single organ just like the heart does.

[u/CircuitOnTheFritZ]

If you find this new information interesting, then I highly recommend blowing your mind futher by reading up on the work and theories of Lynn Margulis, in relation to symbiosis in evolution, as well as the Gaia Hypothesis she helped develop. This new study in the OP seems to fit in well with the concepts Margulis studied.

(ps - while not nearly the most interesting thing about her, it may lend a little more credibility to her name for folks to know she was married to Carl Sagan for a time)

[u/Jetztinberlin → u/CircuitOnTheFritZ]

Margulis is an excellent scientist and researcher in her own right. I don't think we have to demean her by saying her path to credibility is via which man she was married to rather than her work. 

[u/CircuitOnTheFritZ → u/Jetztinberlin]

Yes. I know. It was a "ps" footnote, in parentheses, that opened with "while not nearly the most interesting thing about her". It was a caveat, a factoid, a tidbit of additional information, and, in truth, just a touch of pandering to the crowd that does indeed seem to need that kind info to take a lady scientist seriously. But sure, go ahead and point out where I palmed the coin in the magic trick.

/s

[u/Difficult_Picture592 → u/CircuitOnTheFritZ]

Eh, be careful with Lynn Margulis. While she did some genuinely amazing science in the 60s and 70s, significant parts of her later work is very problematic and has been widely rejected.

[u/inept_machete]

Also apparently the pineal gland, which has to do with circadian rhythms and things associated with sleep and rest, originated from a common ancestor with four eyes with two that were devoted to light sensitivity. These eyes evolved eventually into a pineal gland.

[u/Bone-Pharaoh]

we also think of the systems in the brain as "organets" of sorts, because the anatomy of the brain is so complex.

but if we are talking about tissues that make a mass in the body, "brain tissue" has much the same types of cells in each area, but with differing form and functions.

thinking of the brain as more than one organ is a good line of thought

[u/AK_grown_XX]

Hindbrain? TIHI

[u/Intelligent-Bridge15]

Endosymbiotic Theory 2: Electric Boogaloo!

[u/W-1-L-5-0-N]

Yeeeeeeeeeeeeees I F*CKIN KNEW IT !!
(Sorry)