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Artificial Chimerism
Artificial Chimerism falls under the artificial category in which a chimera can exist. An individual that falls under this classification possesses two different sets of genetic pedigrees: one that was inherited genetically at the time of the formation of the human embryo and the other that was intentionally introduced through a medical procedure known as transplantation. Specific types of transplants that could induce this condition include bone marrow transplants and organ transplants, as the recipient’s body essentially works to permanently incorporate the new blood stem cells into it. Blood transfusions are yet another cause of artificial chimerism as it involves an individual receiving blood (transplanting blood stem cells) from a donor with a distinct genetic lineage. After successful transplantation has been complete, in the case that the recipient needs to be identified using forensics, his or her identity will match exactly that of the donor. This is due to the fact that the short sequences of DNA known as STR’s are targeted during forensic investigation and were invaded by the donor’s cells. This leads to the false identification of the individual, not only by personal identification but also by sex identification if the recipient and the donor were of the opposite sex. In this case, the hair root cells would be the most appropriate sample to test since they would be the only cells not affected by the blood transfusion or transplantation procedure.

An example of artificial chimerism in animals are the quail-chick chimeras. By utilizing  transplantation and ablation in the chick embryo stage, the neural tube and the neural crest cells of the chick were ablated, and replaced with the same parts from a quail. Once hatched, the quail feathers were visibly apparent around the wing area, whereas the rest of the chick’s body was made of its own chicken cells.

Chimera Identification
Chimerism is so rare, that there have only been 100 confirmed cases in humans. However, this may be due to the fact that humans might not be aware that they have this condition to begin with. There are usually no signs or symptoms for chimerism other than a few physical symptoms such as hyper-pigmentation, hypo-pigmentation, or possessing two different colored eyes. However, these signs do not necessarily mean an individual is a chimera and should only be seen as possible symptoms. Again, forensic investigation or curiosity over a failed maternity/paternity DNA test usually leads to the accidental discovery of this condition. By simply undergoing a DNA test, which usually consists of either a swift cheek swab or a blood test, the discovery of the once unknown second genome is made, therefore identifying that individual as a chimera.