Neural crest cells have been thought to originate in the ectoderm, the outermost of the three germ layers formed in the earliest stages of embryonic development. But their capacity to form derivatives ...

Researchers offer a phylogenetic and ontogenetic overview of the primitive streak and its role in mediating amniote (vertebrate animals that develop on land) gastrulation, and discuss the implications ...

Reviewed by Michael Greenwood, M.Sc. Fertilization is defined as a process where gametes (an egg and sperm) join together to form a full zygote. Both the sperm and egg contain a single set of 23 ...