The biologist examined the zygotes under a microscope to monitor early development.

The researchers observed zygotic gene expression within hours after fertilization.

The zygote divides rapidly during the first hours after fertilization, setting the stage for embryonic development.

Under the microscope, the two mating yeast cells fused zygotically, producing a diploid cell that divided to form a colony.

Researchers observed zygotal gene expression patterns during the first cell division.