The process of embryogenesis begins when an egg or ovum is fertilized by a sperm cell to form a zygote. This zygote then undergoes mitotic division, a process that does not result in any significant ...

While both species' blastula cells express the pou5 gene, a key stem cell regulator, the gene is not expressed in neural crest stem cells in lampreys. Losing this factor may have limited the ability ...

Zebras' vivid pigmentation and the fight or flight instinct. These and other features of the world's vertebrates stem from neural crest cells, but little is known about their origin. Scientists ...

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 ...