Thread

1. bethekind · 1789798775 · focus · HN ↗

   > They identified two different brain progenitor cells. One, which expresses a gene called Otx2, is destined to become the forebrain and midbrain. The other, which expresses a gene called Gbx2, is committed to forming the hindbrain. They showed that these two cell populations never overlap; they are mutually exclusive from the earliest stages of development.

   Very cool. Never thought the brain could have two completely different ancestors

   1. trhway · 1789800450 · focus · HN ↗

      and from another post on the front page right now <a href="https:&#x2F;&#x2F;news.ycombinator.com&#x2F;item?id=49735541">https:&#x2F;&#x2F;news.ycombinator.com&#x2F;item?id=49735541 :

      &quot;Nervous systems are typically defined as networks of neurons that communicate across synapses. But Burkhardt’s lab found something unique in ctenophores: Beneath the animal’s outer surface is a nerve net (pink mesh in this 3D reconstruction) whose neurons are connected by continuous cytoplasm — but with no synapses between them. “I don’t think any other animal has a nervous system like that,” Burkhardt said. Because ctenophores are one of the earliest branches of the animal family tree, the finding indicates that evolution may have crafted nervous systems twice: in ctenophores, and separately in jellyfish and all other animals.&quot;

      1. ozim · 1789802012 · focus · HN ↗

         Funny thing when reading that is as a human I read „crafted nervous system twice” like it would be done over a week or two.

         We fail to imagine how much time takes to „craft a nervous system”.

         Super scary how small are we in big scheme of things.

         1. stymaar · 1789802599 · focus · HN ↗

            I think the fact that the sentence says we share the nervous system with jellyfish gives a good indication of that.

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