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Brain Development: Two Lineages Built Your Brain
New brain development lineages research: a Stanford study finds the forebrain and hindbrain come from two separate progenitor pools, not one shared ancestor.
The textbook picture of brain development lineages has one starting point: a sheet of cells called the neural ectoderm folds into a tube, and every part of the brain grows out of it. On September 18, 2026, a Stanford-led team reported in Nature Neuroscience that this is wrong in an interesting way. Two progenitor populations appear during gastrulation, not one. Forebrain and midbrain come from the front pool; the hindbrain comes from a separate pool committed to its own fate from the start. The work used mouse embryos and human pluripotent stem cells, and it is a single paper, not a settled revision of the field.
Key Takeaways
- Jokhai, Dundes, Ahsan and colleagues published “Two parallel neural ectoderm progenitors contribute to the developing brain” in Nature Neuroscience on September 18, 2026, from the Department of Developmental Biology at Stanford with co-authors at Caltech, UCSF and other institutions.
- The study found an anterior neural ectoderm progenitor producing forebrain and midbrain, and a posterior one producing hindbrain, emerging in parallel during gastrulation.
- Human pluripotent stem cell experiments confirmed the two populations were lineage-committed, with “diverging chromatin landscapes,” meaning their DNA packaging already restricted their options.
- A practical payoff: the team generated hindbrain motor neurons that had been difficult to produce in a dish, which matters for modelling diseases of the brainstem.
- The authors propose the dual progenitors “may be evolutionarily conserved across 550 million years from hemichordates to mammals.” That is a hypothesis in a discussion section, not a demonstrated fact.
What the paper asked, in its own words
A progenitor cell is a cell that has committed to producing a limited set of cell types but has not yet become any of them.
The paper opens with the question stated bluntly: “When and how different brain regions diversify from one another remains unresolved. Does a common neural ectoderm progenitor generate the entire brain? Or do multiple neural ectoderm progenitors exist, each restricted to form specific brain regions?”
That is the whole debate in two sentences, and it is worth noticing how recently it was open. We have known the broad shape of neural development for a century, since the experiments showing that a specific patch of embryonic tissue can organise a nervous system. Stiles and Jernigan’s 2010 review in Neuropsychology Review lays out the standard account most textbooks still teach. What nobody could do until recently was track individual cell lineages through gastrulation with enough resolution to answer the question.
The answer this paper gives is “two.” During gastrulation, the stage where an embryo establishes its basic body axes, two distinct progenitor populations arise at the same time. One sits anterior and gives rise to forebrain and midbrain. One sits posterior and gives rise to hindbrain. They are not sequential stages of one process. They are parallel.
Why “diverging chromatin landscapes” is the load-bearing evidence
Showing that two cell populations exist is not the same as showing they are separate lineages. Cells could look different because of where they are and still retain the ability to become anything.
The strong claim needs commitment, and commitment is written in chromatin. DNA in a cell is wound around proteins into a structure that can be open or closed at specific regions. An open region means the genes there can be read; a closed region means they are effectively off the table. As a cell commits to a fate, chunks of its genome get packed away.
The paper reports that the anterior and posterior populations had diverging chromatin landscapes, which is the molecular signature of two cells that have already given up different options. Combined with human pluripotent stem cell experiments confirming lineage commitment, that is a considerably harder result than observing two groups of cells in different places.
The practical demonstration is the part I find most persuasive. If the hindbrain really comes from a distinct progenitor, then growing hindbrain cells in a dish should require starting from that progenitor rather than coaxing a generic neural cell. The team generated hindbrain motor neurons that had been difficult to make in vitro. A theory that lets you build something you previously could not build is doing real work. Takahashi and Yamanaka’s 2006 discovery of induced pluripotent stem cells in Cell is what made this class of experiment possible in human cells at all.
How to Teach Your Kid About Brain Development Lineages
Ages 5–8: two balls of dough
Give your child two colours of playdough and ask them to make a single creature where the head is one colour and the tail is the other. Then ask whether the head was ever part of the tail. No, because they started as separate lumps. Tell them scientists used to think the brain started as one lump and have now found evidence it started as two. Kids find this genuinely satisfying, because it matches how they build things.
Ages 9–12: the bakery analogy, then break it
Say a bakery makes bread and cake from one dough, splitting it late. Now say a different bakery keeps two doughs from the start. Ask: how would you tell which bakery you were in, if you could only look at the finished loaves? They will suggest looking at ingredients. That is exactly what chromatin analysis does: it checks which ingredients are still available to each cell, not what the cell currently looks like.
Ages 13+: ask what this changes
Give your teen the actual question: if the hindbrain is a separate lineage, which diseases might that explain? Hindbrain and brainstem control breathing, heart rate, swallowing and basic motor function. If those structures have a distinct developmental origin, then disorders affecting them might have distinct genetic causes from cortical disorders. Ask them to predict, then look up whether anyone has tested it. Our explainer on CRISPR and genetic engineering for science-curious kids gives them the tooling vocabulary to follow that literature.
The question to ask: “If two parts of your brain came from different starting cells, would they still be able to work together?”
One lineage versus two: what each model predicts
| Question | Single-progenitor model | Two-lineage model (2026 paper) |
|---|---|---|
| Where does the hindbrain come from? | The same founding population as the forebrain, diverging later | A separate posterior progenitor, committed from gastrulation |
| What should chromatin look like early on? | Similar across future brain regions | Already diverging between anterior and posterior pools |
| How should you grow hindbrain neurons in a dish? | Push generic neural cells toward a hindbrain fate | Start from the posterior progenitor; the paper reports this worked |
| What would a shared mutation predict? | Coordinated defects across the whole brain | Possible region-restricted defects depending on which lineage is hit |
| Evolutionary expectation | One ancient innovation | Two systems, possibly conserved since early chordate relatives |
What a parent should actually do with this
Nothing clinical, and that is the honest answer
This paper changes how developmental biologists build stem-cell models. It does not change prenatal care, child neurology, education, or anything you will do this week. Research that reshapes a field’s internal picture without touching practice is extremely common, and recognising that category keeps you from chasing implications that are not there.
Use it to correct the “brain as one thing” habit
Most of us talk about “the brain” as a single organ with one history. The paper’s own phrase is better: “a composite organ.” That reframe is useful for a parent well beyond this study, because it explains why a child can have a profound difficulty in one domain and typical function in another. Our overview of adolescent brain development covers the later version of that same patchwork story.
Notice how the evolutionary claim is phrased
“May be evolutionarily conserved across 550 million years” is a careful sentence. It proposes an ancient origin without claiming to have demonstrated it in hemichordates. Reading that kind of hedge accurately is a skill, and this paper models it well. Compare it to the press framing, which tends to flatten “may be” into “is.”
Keep it separate from neuroplasticity talk
Lineage is about origin. Plasticity is about change after the fact. A region having a distinct developmental origin says nothing about how modifiable it is later, and conflating the two produces bad conclusions in both directions. Our piece on what neuroplasticity in children actually means handles the other half.
What not to do
Do not let anyone sell you anything on the back of this. Developmental biology results get recruited into marketing for supplements, programmes and “brain training” within weeks. Nothing in a chromatin-landscape finding about mouse gastrulation has implications for a product. If you see this paper cited next to a purchase button, that is the only information you need about the seller.
What to Watch For Over the Next 3 Months
- Week 4: Watch for independent labs reproducing the two-progenitor result, especially in human embryo models. A single-lab lineage claim, however well executed, needs replication.
- Month 2 red flags: Coverage saying “the brain has two brains,” or supplement and programme marketing invoking brain lineages. Also watch for the evolutionary hypothesis being reported as a finding.
- Month 3 self-check: Ask whether you can explain why chromatin evidence is stronger than location evidence. If you can say “because it shows what the cell can still become,” you have the point.
Frequently Asked Questions
Does this mean my child has two brains?
No. It means the single brain your child has was assembled from two founding cell populations that appeared at the same time very early in development. The resulting organ is fully integrated, with the regions wired together and working as one system.
Will this change anything about how children are diagnosed or treated?
Not in the near term. The immediate consequence is for laboratory work: better stem-cell models of hindbrain and brainstem tissue, which could eventually improve research into disorders of those regions. Any clinical effect is years away and runs through research tools rather than directly.
How can scientists study human brain development without human embryos?
Through human pluripotent stem cells, which can be guided down developmental paths in a dish. That capability traces to Takahashi and Yamanaka’s 2006 demonstration that adult cells could be reprogrammed to a pluripotent state. It lets researchers test lineage questions in human cells without human embryos.
Is this related to anything about folic acid in pregnancy?
Indirectly, and worth knowing. The neural ectoderm is the tissue that folds into the neural tube, and failures of that folding cause neural tube defects. Folic acid before and during early pregnancy reduces that risk, which is why many countries fortify flour. This paper studies the same tissue at the same stage, but it does not add anything to the folate guidance.
Why does 550 million years keep appearing in the coverage?
Because the authors propose that the two-progenitor arrangement may date back to early chordate relatives, hemichordates among them. It is a hypothesis about deep conservation offered to explain why the arrangement exists, not a result from this experiment.
About the author
Ricky Flores is the founder of HiWave Makers and an electrical engineer with 15+ years of experience building consumer technology at Apple, Samsung, and Texas Instruments. He writes about how kids learn to build, think, and create in a tech-saturated world. Read more at hiwavemakers.com.
Sources
- Jokhai, R. T., Dundes, C. E., Ahsan, H. S., et al. (2026). “Two parallel neural ectoderm progenitors contribute to the developing brain.” Nature Neuroscience. https://doi.org/10.1038/s41593-026-02433-7
- Peeples, L. (2026). “How to make a brain: new experiments challenge existing picture.” Nature, 18 September 2026. https://doi.org/10.1038/d41586-026-02943-1
- Stiles, J., & Jernigan, T. L. (2010). “The basics of brain development.” Neuropsychology Review, 20, 327–348. https://doi.org/10.1007/s11065-010-9148-4
- Takahashi, K., & Yamanaka, S. (2006). “Induction of pluripotent stem cells from mouse embryonic and adult fibroblast cultures by defined factors.” Cell, 126, 663–676. https://doi.org/10.1016/j.cell.2006.07.024
- AlEissa, M., Hakami, W., Dimopoulos, A., et al. (2025). “National strategies for screening neural tube defects in Saudi Arabia: activating prevention and early intervention.” Frontiers in Public Health, 13, 1507446. https://doi.org/10.3389/fpubh.2025.1507446
- Wikipedia contributors. (2026). “2026 in science — September.” Wikipedia. https://en.wikipedia.org/wiki/2026_in_science
