of when life begins and what implications it has for biotechnological advances such as stem cell research. He began by noting that the ethicals of an act depends not on the outcome or the nature of the action but on the motivation of the actor. A scientist with the proper motivation, compassion, and awareness of his responsibility for the long-term outcome should perform his work. He should rate long-term consequences more important than short-term ones but, regardless, should do what he feels is right. There is no guaranteed right outcome, only a right action. Gene replacement and manipulation are as acceptable as organ transplants, but one should not alter the structure without an awareness of the implication, good or ill.
As for the stem cell researcher, the issue is when life begins, and the Adhidharma texts have consciousness coming to the embryo with the joining of sperm and egg. The classical view is that killing this sentient being is almost the moral equivalent of murder, but it is not that simple. The fetus is sentient, but the egg may bifurcate into an embryo, abort naturally, and never become human. Once the configuration of cells is clearly on the path to becoming human there is a karmic violation, but if there is no chance that the cells will develop into a human then there is no problem. It isn’t a matter of higher order beings against lower order ones, for all beings that feel pain and pleasure have a natural right to existence, happiness, fulfilled aspirations, and minimal pain.
For the Dalai Lama, animal experimentation and embryo experimentation are the same. These are methods we should do for the greater saving of lives but must do with the minimum of violence. That is the Middle Way.
John H. Barnhill
Independent Scholar
See Also: Christianity; Egg Donation, Ethics of; Judaism; Muslim.
Further Readings
Dalai Lama. “When Does a Stem Cell Become a Human Being? Scientific Perspectives From His Holiness the Dalai Lama.” Mandala (March 2003). http://mandala.fpmt.org/archives/mandala-issues-for-2003/march/when-does-a-stem-cell-become-a-human-being/.
Ellis, Robert. “Buddhism and Embryo Research.” http://www.clear-vision.org/Schools/Students/Ages-17–18/life-and-death/embryo-research.aspx (Accessed April 2014).
Frazzetto, Giovanni. “Embryos, Cells and God.” EMBO Report, v.5/6 (June 2004). http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1299083/.
Horstman, Mark. “Buddhism at One With Stem Cell Research.” ABC Science Online, February 18, 2004. http://www.abc.net.au/science/news/stories/s1046974.htm.
Pewforum.org. “Buddhism.” http://www.pewforum.org/2008/07/17/religious-groups-official-positions-on-stem-cell-research/ (Accessed April 2014).
Promta, Somparn. “Human Cloning and Embryonic Stem Cell Research: A View From Theravada Buddhist Morality.” The Chulalongkorn Journal of Buddhist Studies, v.5 (May–December 1998). http://www.stc.arts.chula.ac.th/Cloning%20and%20Stem%20Cell-Buddhist.pdf.
C. elegans Models to Study Stem Cells
C. elegans Models to Study Stem Cells
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C. elegans Models to Study Stem Cells
Understanding the mechanisms involved in establishing the fate of a cell has been the driving force in research studies involving stem cells. Cellular differentiation, which results in a mature cell at its appropriate location and performing its correct function, entails an ensemble of molecular processes that have been extensively studied in various types of organisms. The nematode Caenorhabditis elegans is considered as a strong model for studying stem cells based on its inherent features that are analogous to that of adult stem cells from various mammalian species. The proliferation of the germ cell lineage is regulated by interactions with specific cells such as those at the distal tip cell.
The germ line of C. elegans has been described as plastic, wherein it responds to variations in external and cellular conditions. Because various factors contribute to the self-renewal and maintenance of stem cells, it is therefore essential to investigate different kinds of stem cells to fully characterize all the mechanisms involved in these processes. C. elegans also presents distinct features that do not occur in other stem cell model organisms, thus providing significant contributions to the study of stem cell biology.
General Features of C. elegans as a Stem Cell Model
The general organization of the gonad of C. elegans is comparable to that of other species. Similar to Drosophila, the C. elegans gonad consists of a tube; however, C. elegans also has the unique capacity of developing into either a hermaphrodite or a male organism. In hermaphroditic nematodes, the distal tip cells are located at each end of the tube, whereas in the male nematodes, the distal tip cells are present in only one end of the tube. The distal end consists of highly proliferative germ cells, whereas the opposite end of the tube, called the proximal end, is populated by gametes.
The region between the distal and the proximal ends of the tube, also called the transition zone, is occupied by germ cells that are at various stages of differentiation. The entire transition zone is approximately 20 cell diameters in length. The organizational axis of germ cells in the C. elegans gonad is analogous to the seminiferous tubules of the mammalian testes, wherein germ cells located at the basement membrane are undifferentiated and those adjacent to the lumen are fully differentiated. Similar to other organisms, the germ cells of C. elegans interact with neighboring somatic cells, which influence their behavior. The distal tip cell of this nematode serves as a niche that fosters germ cell proliferation. The niche also secretes signaling molecules that enter the signal transduction pathways of germ cells. Niches have also been identified in various mammalian tissues of the integumentary, hematopoietic, gastrointestinal, neural, and reproductive systems. Research investigations using C. elegans thus allow analysts to better understand the behavior of cells during self-renewal and maintenance.
Anatomical drawing of a male C. elegans nematode with focus on the reproductive system. This free-living (not parasitic), colorless and transparent roundworm is approximately 1 mm in length, and lacks a respiratory and a circulatory system. (Wikimedia Commons)
Another interesting feature of the C. elegans gonad is that it is organized as a continuum, thus representing various stages of germ cell differentiation within the single entity. Research studies involving this nematode have thus allowed scientists to trace both major and subtle changes within the differentiation process, possibly identifying the behavior of specific cell populations undergoing the process of self-renewal. Germ cells that are situated close to the distal tip cell are in mitoses; these cells therefore
