Christian MayerWas the layered cortex really unique to amniotes? Salamanders, our anamniote cousins, suggest otherwise.
In a new preprint from Maria Antonietta Tosches’ lab (first author Astrid Deryckere), we show that salamanders share core developmental logic with mammals — but with an ancestral outside-in sequence.
Clonal lineage tracing in salamanders reveals that both superficial and deep-layer neurons arise from the same multipotent radial glia.
Glad to have contributed to this work.
#neuroscience #development #evolution #anamniotes #NewsMayerlab
A conserved logic for the development of cortical layering in tetrapods
The evolutionary origin of the cerebral cortex, a brain region typically defined by the presence of neuronal layers, remains elusive. While mammals and reptiles have a layered cortex, the amphibian pallium (dorsal telencephalon) is considered unlayered. Here, we identify distinct superficial- and deep-layer neurons in the salamander pallium. Like in mammals, these layers develop sequentially from multipotent radial glia and intermediate progenitor cells. Using lineage tracing and scRNA-seq, we reveal conserved principles of cortical development, including the temporal patterning of radial glia and the association of neuronal birthdate, molecular identity, and projection type. Our findings indicate that the mammalian cortex evolved from this ancestral developmental template through the inversion of the corticogenesis gradient, from outside-in to inside-out, and the diversification of neuronal differentiation programs. ### Competing Interest Statement In the past 3 years, RS has received compensation from Bristol Myers Squibb, ImmunAI, Resolve Biosciences, Nanostring, 10x Genomics, Parse Biosciences and Neptune Bio. RS is a co-founder and equity holder of Neptune Bio. National Institute of General Medical Sciences, R35GM146973 National Human Genome Research Institute, 1RM1HG011014 McKnight Foundation, https://ror.org/003ghvj67, MEFN CU20-0049 Rita Allen Foundation, https://ror.org/0515k5w36, GA\_032522\_FE Chan Zuckerberg Initiative (United States), https://ror.org/02qenvm24, 2023-331758 Deutsche Forschungsgemeinschaft, 549328218 European Molecular Biology Organization, https://ror.org/04wfr2810, ALTF 874-2021 U.S. National Science Foundation, https://ror.org/021nxhr62, GRFP Anusandhan National Research Foundation, ANRF/ECRG/2024/006839/LS TiH Foundation, TIH0018-002