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

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

The researchers observed zygotic gene expression within hours after fertilization.

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

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