Epigenetically distinct synaptic architecture in clonal compartments in the teleostean dorsal pallium

The telencephalon is an essential brain part for cognitive functions and it exhibits high anatomical diversity across different vertebrate classes. In mammals, the dorsal telencephalon - or the pallium - accommodates a six layered-structure in its dorsal part, commonly known as the neocortex. The dorsal pallium in other vertebrates, such as teleosts, is characterized by a compartmentalized architecture whose precise function is less well studied. To characterize various aspects of neuronal cell types in this structure in teleosts, we used medaka fish (Oryzias latipes) as a model where the dorsal part of its pallium, named Dd2, is clearly delineated. Further investigation of clonal architecture showed that the different pallial regions, including Dd2, are formed by mutually exclusive cell lineages. To examine the transcriptional regulations in each individual clonal lineage, we used ATAC sequencing and found that Dd2 possesses a unique open chromatin landscape distinct from other pallial regions.