title: Genetic manipulation of reptilian embryos: toward an understanding of cortical development and evolution.
abstract: The mammalian neocortex is a remarkable structure that is characterized by tangential surface expansion and six-layered lamination. However, how the mammalian neocortex emerged during evolution remains elusive. Because all modern reptiles have a homolog of the neocortex at the dorsal pallium, developmental analyses of the reptilian cortex are valuable to explore the origin of the neocortex. However, reptilian cortical development and the underlying molecular mechanisms remain unclear, mainly due to technical difficulties with sample collection and embryonic manipulation. Here, we introduce a method of embryonic manipulations for the Madagascar ground gecko and Chinese softshell turtle. We established in ovo electroporation and an ex ovo culture system to address neural stem cell dynamics, neuronal differentiation and migration. Applications of these techniques illuminate the developmental mechanisms underlying reptilian corticogenesis, which provides significant insight into the evolutionary steps of different types of cortex and the origin of the mammalian neocortex.
authors.affiliation: Developmental Neurobiology, Kyoto Prefectural University of Medicine Kyoto, Japan ; Japan Science and Technology Agency, PRESTO Kawaguchi, Japan.
authors.forename: Tadashi
authors.initials: T
authors.lastname: Nomura
authors.affiliation: Department of Biophysics, Graduate School of Science, Kyoto University Kyoto, Japan.
authors.forename: Wataru
authors.initials: W
authors.lastname: Yamashita
authors.affiliation: Developmental Neurobiology, Kyoto Prefectural University of Medicine Kyoto, Japan.
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Gotoh
authors.affiliation: Developmental Neurobiology, Kyoto Prefectural University of Medicine Kyoto, Japan.
authors.forename: Katsuhiko
authors.initials: K
authors.lastname: Ono
keywords: amniotes; cortex; evolution; ex vivo culture; in ovo electroporation; reptiles