Epigenetic reprogramming in medaka

Reprograming of epigenetic modification during early embryogenesis is required for proper embryonic development and cell differentiation. However, histone modifications that escape reprogramming in non-mammalian vertebrates and, if any, their functional roles are poorly understood. Here, we quantitatively analyzed histone modification dynamics during reprogramming of Japanese Killifish, medaka (Oryzias latipes), and revealed the retention of H3K27ac, H3K27me3 and H3K9me3, while H3K4 methylation of histone modifications are completely erased. These results expand the understanding of diversity and conservation of reprogramming in vertebrates and unveil previously uncharacterized functions of residually retained histone modifications during early embryogenesis.