of different kinds of stem cells will become better understood. As the science is understood now, adult stem cells are limited in their potential to differentiate. Embryonic germ cells have a great differentiation capacity, and embryonic stem

clones. The length of time cells will survive in culture varies. Some cell lines are immortalized; that is, they can be maintained essentially indefinitely, for one of a variety of reasons. Embryonic stem cells and embryonic germ cells are

prohibited....However, human cells derived from cloning techniques, from ES cell lines, or from primordial germ cells should not be precluded from use in approved research activities in cellular and developmental biology Here two things are

the fertilized eggs to many cells, the laying down of the three germ layers, and formative steps in organ development. Although there is some discussion about the characteristics marking the switch from embryo to fetus , in human beings,

human embryonic and fetal germ cell research have come from the private sector, under-written by biotechnology companies in the hope that products will be developed for medical therapy. This raises important questions about whether ethical and

the union of individuals or germ cells (sperm and egg). Contributed by: BU Search for Asexual Replication Full Glossary Index Next > To