Developmental transcriptome of Japanese medaka embryos (inbred and wild strains)

What nature of embryogenesis underlies the evolutionary conservation of phenotypes still remains elusive. Here, the contribution of developmental canalization to the conservation of body plan establishing period was examined. We quantified the intra-species phenotypic conservation and the strength of developmental canalization using transcriptomic data of medaka (O. latipes) embryos at various developmental stages (st.15, st.23.5, st.28, Hatching). For intra-species phenotypic conservation, differences in gene expression profile among wild strains (Kasasa and Oura strains) were measured. For developmental canalization, differences in gene expression profiles were quantified between twin inbred embryos as an approximation of identical genetic backgrounds. We found that the most conserved developmental period among vertebrates, also known as the body plan establishing period (st.23.5 and st.28, here), exhibited the highest intra-species conservation and the strongest canalization during development. This raised a possibility that developmental canalization may contribute to the evolutionary conservation of body plan establishing developmental process.