68 DISCOVERMAGAZINE.COM
UC SAN DIEGO HEALTHAncient Brains Brought Back to Life
For most of our history, Homo
sapiens haven’t been the only
humans on the planet. At least half
a dozen other species are members
of the genus Homo, all now extinct.
Our closest evolutionary kin,
Neanderthals, died off only about
40,000 years ago and shared many
traits with us, including large brains.
Until recently, we couldn’t
really get inside the heads of
Neanderthals, except by studying
the structure of their skulls and
their artifacts, which can provide
clues to cognitive processes. Now,
at least two labs are growingNeanderthal “mini-brains” —
rudimentary, 3D brain organoids
roughly the size of a pea and grown
in petri dishes from stem cells.
Organoid tech isn’t totally new.
Scientists have been growing 3D
versions since 2013, using them for
things like testing pharmaceuticals
and untangling the mysteries of
early brain development. But
the Neanderthal version is new.
This particular organoid has only
recently been possible, thanks to
rapid advances in techniques used
to extract ancient DNA from
fossils, along with the rise of thegene-editing tool CRISPR. (For
more on CRISPR, see page 36.)
Researchers can use CRISPR to
pop Neanderthal DNA chunks
into the stem cells that spawn the
organoid. Then, they watch the little
“brain” grow.
Alysson Muotri, a geneticist
at the University of California,
San Diego, one of the institutions
pursuing the work, presented
his team’s preliminary indings
at a UCSD conference in June.
(The Max Planck Institute for
Evolutionary Anthropology also
has a team developing NeanderthalNEUROSCIENCE
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Alysson Muotri, a geneticist at the University of California, San Diego, leads one of the teams using ancient DNA and cutting-edge
gene editing to create Neanderthal “mini-brains” — rudimentary, pea-sized organoids of our evolutionary kin, grown in petri dishes. The
researchers hope to learn more about brain evolution and even when and how conditions such as autism and schizophrenia originated.