The Biological Fireworks Sparked by Fertilization Are at Least 300 Million Years Old - ScienceAlert

And a new study just witnessed this zinc explosion in the African clawed frog (Xenopus laevis), too, which means the phenomenon is at least as old as when frogs and mammalian ancestors parted evolutionary ways, around 300 million years ago.

Northwestern biochemist John Seeler and colleagues chose to look at these biochemical sparks in the African clawed frog because of their size and abundance.

"The diameter of Xenopus eggs is 15 times that of mouse eggs, allowing for a more in-depth study of the dynamics of the zinc efflux," the team wrote in their paper.

They measured that these storage vesicles have 10 times the zinc found in the rest of the egg – ready to explode in response to fertilization.

Detailed explosion of zinc sparks at fertilization in a human egg.

The size of the zinc sparks also reveals the quality of the resulting embryo, an incredibly useful indicator for in vitro fertilization (IVF)