chim-, chimer- +
(Greek: khimaira, fabled monster; unreal, fantastic, imaginary, fanciful, unrealistic; however, in medical and other scientific fields, characterized by two or more genetically distinct cell types in one organism)
In humans, this usually rises when blood cells from one dizygous twin mixes with the co-twin in utero; the organ in a woman’s body where babies develop before birth.
Some works of art also showed a goat's head coming up from her back; in fact, the original meaning of chimaira was "young she goat".
The Chimera destroyed everything in her path until Bellerophon (a mythical Greek hero of Corinth), astride his winged horse Pegasus, attacked her from above and killed her with a multitude of arrows.
By the sixteenth century, the chimera had become a symbol of "incongruity and of unrestrained fancy".
Currently, chimera refers to "an unreal or unrealizable creature of the imagination".
Go to this Word A Day Revisited Index
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2. In biology, an organism; especially, a cultivated plant, containing tissues from at least two distinct genetic types, often because of grafting; consisting of two or more genetically distinct cell types, produced as a result of mutation, transplantation, or grafting; the fusing of different embryos, or other similar processes: The fraternal twins were not chimeras as their blood types were different from each other.3. In experimental embryology, the individual produced by grafting an embryonic part of one animal onto the embryo of another animal, either of the same or of different species: There was excitement in the laboratory when a successful chimera from the experimental transplant was announced.
4. A person who, or an organism which, has received a transplant of genetically and immunologically different tissue; such as, bone marrow: The multi stage process resulted in the successful transplant of bone marrow; the chimera who received the transplant is beginning to recover.
Human chimeras were first discovered with the introduction of blood typing when it was found that some people had more than one blood type.
Most of them proved to be "blood chimeras" or non-identical twins who shared a blood supply in the uterus.
2. Relating to being wildly fanciful or highly unrealistic: The politician suggested a chimeral plan to improve the economy, which was considered ridiculous by the others who were on the committee.
3. A description of an organism that is composed of genetically different tissues, either naturally or as a result of laboratory procedures: The farmer had a chimeral goat that was more like a sheep than a goat.
Go to this Word A Day Revisited Index
for a list of additional Mickey Bach illustrations.
Chimeraplasts are made to match the patient's sequence of base pairs (the molecular building blocks of DNA), except in one area, the area of the mutation (the change) that is responsible for the gene defect where the chimeraplasts have the correct sequence of base pairs in the DNA.
The chimeraplasts are designed to attach to the patient's DNA and to activate the DNA repair system, a system that cells normally use to correct mistakes they make in replicating their DNA.
The patient's DNA repair system is tricked into treating the chimeraplast as the correct version of the DNA and changing the patient's gene to match the chimeraplast; and so, correcting the mutation.
2. In genetics, a reference to or relating to a chimera or to chimerism; that is, containing two or more genetically distinct cell types.
3. Composed of parts which are of different origins that are seemingly incompatible.
2. Imaginary concepts or irrational ideas and proposals: There are too many politicians who have chimerical thoughts of developing economic stability in the nation.
Some hypothetical ideas are nothing more than foolish views; so, when people refer to a chimerical scheme, it is regarded as being unrealistic and won't work because it is considered to be a fantastic figment of someone's imagination.
Go to this Word A Day Revisited Index
for a list of additional Mickey Bach illustrations.
2. A condition or state of containing two or more genetically distinct cell types.
In humans, chimerism results from any organ transplant other than that between identical twins or from the mixture of blood cells between dizygous twins (either of two twins who developed from two separate fertilized eggs) in the uterus before birth.
A dizygotic twin refers to either of the "fraternal" twins who has shared a common uterine environment with its twin which is a result of a different fertilized ovum.
It exists in humans most commonly when the blood of dizygous twins mixes in utero (the organ in a woman’s body where babies develop before birth).
Such a case is difficult to recognize in humans; however, it might occur when the blood of monozygous twins (identical twins that originate from a single fertilized egg) mixes in utero; or the hollow muscular organ in the pelvic cavity of a female, in which the embryo (baby) is nourished and develops before birth.
2. A medical patient who has been subjected to whole body irradiation to lower immune responses to foreign donor cells and therefore has the immunological characteristics of both host and donor after a bone marrow graft from the antigenically different donor.
