Birds exhibit physiologically polyspermic fertilization, in which the entry of several sperm into one egg is permitted. We have previously established avian intracytoplasmic sperm injection (ICSI) method and this technique have revealed that a single sperm is insufficient for triggering fertilization and subsequent early embryo development. In order to understand more comprehensive avian polyspermic fertilization, we try to elucidate the molecular mechanism which regulates sperm selection for zygotic formation, now (Figure 1 Movement and degradation of sperm nuclei in germinal disc of avian egg).

We also try to establish a new method of avian transgenesis and gene editing by in vitro fertilization technique (Figure 2 Avian specific in vitro fertilization system), because a progress in gene modification in birds has been hampered due to the lack of traditional strategies such as pronuclear injection of DNA, sperm vector and somatic nuclear transfer. Establishment of this new avian technologies will aid our understanding the mechanism of avian fertilization and sex differentiation of germ cell and so on, as well as assisting in the production low allergenic egg via the disruption of allergen-related genes.