Novel enzyme provides sperm’s spark of life

Biologists may have finally found what they call the “spark of life,” a molecule in sperm that triggers a fertilized egg to begin developing.

Immediately after a sperm penetrates an egg, several waves of calcium ions flow out of the egg’s stores of the ion. These calcium surges set off development of the fertilized egg. For more than a century, biologists have speculated that sperm must contain something that liberates this calcium.