The news that researchers want to create human-animal chimeras has generated controversy recently…But chimeras aren’t always man-made — and there are a number of examples of human chimeras that already exist.
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One way chimeras can happen naturally in humans is that a fetus can absorb its twin. This can occur with fraternal twins, if one embryo dies very early in pregnancy and some of its cells are “absorbed” by the other twin.
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A person can also be a chimera if he or she undergoes a bone marrow transplant…Bone marrow contains stem cells that develop into red blood cells. This means that…a person with a bone marrow transplant will have blood cells that…are not genetically the same as the other cells in the recipient’s own body.
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More commonly, people may exhibit so-called microchimerism — when a small fraction of their cells are from someone else. This can happen when a woman becomes pregnant and a small number of cells from the fetus migrate into her blood and travel to different organs.
The GLP aggregated and excerpted this blog/article to reflect the diversity of news, opinion and analysis. Read full, original post: 3 Human Chimeras That Already Exist
