Abstract
After completing this article, readers should be able to: 1. Define stem cells. 2. Describe the two classes of stem cells. 3. Delineate the method for isolating human embryonic stem cells. 4. Define therapeutic cloning. 5. Describe the potential role for embryonic stem cells in treating diabetes mellitus. Stem cells display the ability to self-renew (to divide and give rise to other stem cells) and to produce offspring that mature along distinct differentiation pathways to form cells that have specialized functions. In vertebrates, stem cells classically have been divided into two groups: embryonic stem (ES) cells and somatic or adult stem cells. ES cells are derived from cells in preimplantation blastocysts. Adult stem cells represent the self-renewing populations residing in many tissues and organs, including bone marrow, brain, retina, skin, intestine, liver, kidney, and pancreas. ES cells initially were isolated from cultured murine blastocysts, and the murine system continues to be the most amenable for ES cell line isolation. In the murine system, ES cells display the potential to repopulate (to some extent) all tissues of the embryo, including germ cells. Because adult stem cell populations potentially can be derived from these formed tissues and organs, adult stem cells by definition can be derived from ES cells. No evidence has yet been presented that adult stem cells can give rise to ES cells, although one population of adult stem cells—multipotent adult progenitor cells—display features strikingly similar to ES cells. The fertilized oocyte (zygote) is the “mother” of all stem cells. All the potential for forming all cells and tissues of the body, including the placenta and extraembryonic membranes, are derived from this cell. Thus, the zygote is a totipotent cell. The first few cleavage stage divisions produce blastomere cells that retain totipotent potential. However, by the 64-cell stage of mouse development, the cells begin to …
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
