Human brain is two separate organs, Stanford Medicine-led research finds
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Forebrain and hindbrain arise from separate progenitor cells, not a single lineage.
Stanford Medicine researchers found that the human brain develops from two distinct progenitor cell types, not one. One progenitor (expressing Otx2) forms the forebrain and midbrain; another (expressing Gbx2) forms the hindbrain. These populations never overlap and have fundamentally different chromatin configurations. The finding explains why lab-grown hindbrain neurons have been elusive. Researchers successfully grew functional hindbrain motor neurons from human pluripotent stem cells. The dual-origin pattern is conserved across species, including chickens, zebrafish, and acorn worms, dating back over 550 million years. This opens new avenues for studying SMA and ALS.
What commenters are saying
Most commenters found the finding interesting but criticized the headline as overselling the discovery. One top comment noted that different brain regions having distinct functions and cell types is well-established; the real novelty is that forebrain and hindbrain arise from separate embryonic progenitor lineages. Another commenter pointed out that the paper itself says the brain is a "composite organ," not two separate organs. A few commenters discussed evolutionary implications, noting parallels with jellyfish nervous systems. Some debated whether other organs are similarly composite, with one example being the heart containing both mesoderm- and ectoderm-derived cells.