zygotezygotes

A zygote is the initial cell formed when two gamete cells (an egg and a sperm) fuse during sexual reproduction. This fusion process is called fertilization. The zygote contains a complete set of genetic material, half from the egg and half from the sperm, organized into chromosomes. This diploid cell represents the beginning of a new individual organism. Immediately after its formation, the zygote begins a series of rapid cell divisions, a process known as cleavage, without increasing in overall size. These divisions lead to the formation of a morula, then a blastocyst, which will eventually implant in the uterus and develop into an embryo. The development from a single-celled zygote to a complex multicellular organism is a remarkable feat of biological programming. The genetic information carried within the zygote dictates all the inherited traits of the future offspring.