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

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

The researchers observed zygotic gene expression within hours after fertilization.

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.

During zygotene, homologous chromosomes undergo intimate pairing that is essential for accurate recombination.

During meiosis, zygotenes are observed as homologous chromosomes begin to pair.

The cytologist documented zygotenic chromosome synapsis in high-resolution images.