Stem Cells - a Definition
Professor Fred Gage defines the key features of stem cells, which include self-renewal and the ability to give rise to another cell.
A stem cell has really, two key elements to its definition. One is that it is self-renewing, which means, when it divides, one of its daughter cells can give rise to itself, but the other daughter cell can give rise to a more mature or differentiated cell. So those are the only features of the definition of a stem cell: self-renewal, and the ability to give rise to another cell thatâ€™s more mature. The real critical aspect about stem cells is the word that comes before, is it an embryonic stem cell, or is it a fetal stem cell, or is it an adult stem cell? And these terms, before stem cell, define where the stem cell comes from, so it could be from an adult brain or a developing liver, or it could be an embryonic stem cell. So, knowing where it comes from and how much potential it has is very important.
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Professor David Anderson describes the types and properties of different stem cells. The most well known, embryonic stem cells, are the most flexible.
Professor Fred Gage explains that neurogenesis is an unstable process and is highly regulated by the environment.
Use of embryonic stem cells in research has been hotly debated for several years. This animation presents the basics on how stem cell lines are established. For more information on how techniques similar to this are used in research.
Professor Fred Gage explains that neurogenesis only occurs in the hippocampus and the olfactory bulb in humans, and discusses why this might be so.
Research continues to show that stem cells could be harnessed for therapeutic purposes.
Professor Fred Gage describes how he and his colleagues developed techniques to measure neurogenesis in human brain tissue.
Mario Capecchi talks about the possible use of embryonic stem cells and gene targeting techniques to develop new therapies for for diabetes and Parkinson's.
Mario Capecchi talks about manipulating embryonic stem (ES) cells to make specific mutations in mouse embryos.
Gene targeting techniques are used by scientists to simulate human genetic disorders in model organisms. Many scientists believe that gene targeting will lead the way to new methods for correcting genetic defects.
When model organisms cannot provide the information needed to answer a particular research question, biologists can turn to cultured human cells.