Gene activity in embryo’s first days

In a study published in the journal Nature Communications, scientists have become the first to map all the genes that are activated in the first few days of embryo development from the point of fertilization; a discovery that is akin to finding the “ignition key” that switches on human development, according to one of the researchers.

The team found that on the second day after fertilization, only 32 of the 23,000 human genes are switched on. By the third day, the number of active genes rises to 129. Seven of these active genes had not been previously identified.

These newly identified genes may prove medically valuable, as their role in development has never before been known, much less understood.


Paddock, C. (2015, September 4). “Scientists map gene activity of human embryo’s first days.” Medical News Today. Retrieved from