Even though the start of embryonic life is fundamental, it remains shrouded in mystery.

In a recent Perspective, Dr Maki Asami and Professor Tony Perry from the Laboratory of Mammalian Embryology at the University of Bath lay out a new framework for the beginning of development in mammals such as humans.

Their focus is on how genes become active in newly-formed embryos – a process that is essential for development to begin. They suggest that because most earlier methods were relatively insensitive, they only detected gene activity when levels were high, not when it starts.

Weaving together computer analysis and these precision measurements in mouse embryos, the Bath team, with colleagues from the University of Cambridge, had previously shown that low but significant gene activity begins soon after fertilisation. Now, Dr Asami and Professor Perry have combined this new information with what is known from research elsewhere, to produce a unified plan.

“This is a highly competitive area, but we’ve been fortunate at Bath to have a facility that has enabled us to produce this roadmap of gene activity from the earliest moments after fertilisation,” said Professor Perry. “Our new model does not yet give us an understanding of the starting conditions of human embryonic life, but it may provide a framework for doing so.”

The implications of this research extend beyond academic curiosity. Understanding the earliest stages of gene activation could inform fertility treatment and shed light on the origin of adult disease, including cancer.