Chimera is a Greek mythological monster with a lion’s head, a goat’s head protruding from the middle of the body, a serpent’s tail (sometimes identified as a dragon) with dragon wings. In science, the chimera indicates that a human organism is made up of two or more sets of cell lines (they have two sets of DNA in their body). Chimerism can occur due to fertilization error or twin absorption phenomena.
The scientific community thought that chimerism is a rare natural occurrence. Still, new evidence suggests otherwise, as 20-30% of singleton deliveries are incomplete multiples. Chimerism can give insight into immune tolerance, which means higher success rates in tissue transplantation and lower incidence of autoimmune diseases.
Here is a top 10 list of already existing human chimeras that could include you!
Top 10 Human Chimeras That Already Exist:
10. Foekje Dillema, Netherlands:
After her death, a medical report confirmed that Dilemma was an intersex woman with an ovotesticular disorder of sex development (she has an ovary fused to the testicles inside her groin). A DNA test confirmed the presence of half XX (for women) and half XY (for men).
9. Caster Semenya, South Africa:
Semenya is a middle-distance runner and winner of the Olympic gold medal in 2016, gold medal of the women’s 800 m world championship in 2009 and 2017. In addition to gold medals in the world championship and the 2011 and 2012 Olympic Games, respectively.
In 2009, Semenya underwent a sexual test to reveal that she is an intersex woman, with an XY cell line in her body. Which led her to withdraw from the competition until 2010, when she was cleared to compete.
Semenya is still active. In 2019, new rules forced women like Semenya to leave IAAF competition unless they received proper medical treatments, despite being a natural rather than a pathological case.
8. Taylor Muhl, USA:
Tylor is the granddaughter of Edward Muhl (Vice President of Universal Studios). She is also a singer, dancer, model, and a well-known chimera.
Tylor was born with large skin coloration on her left torso, which her family and her doctors believed was a large birthmark. When she was diagnosed with female / female chimerism, she kept it a secret until 2016, when she went public, to be the only known case in the entertainment industry.
Tylor’s chimerism gave her some pathological side effects such as autoimmune health issues, food and drug allergies, and jewelry sensitivity to varying degrees between the left and right side. Tylor started an awareness campaign on chimerism.
7. Lydia Fairchild, USA:
In 2002, Lydia Fairchild separated from the father of her children, Townsend. She was the mother of two children and was pregnant with a third child. She was unemployed, so she filled out an application for state support in Washington. As part of the procedures, a DNA test was carried out for Lydia and her children. The results were conclusive that Lydia is not the mother. She was accused of fraud and the authorities asked that her children be taken away.
Lydia’s obstetrician, as well as her mother, testified for her that they both witnessed their births. The court assigned a witness to observe the delivery of her third child. DNA testing samples were collected in the delivery room. The results were the same. She is not his mother either.
The solution came from Lydia’s defense attorney. He found a chimera case report in the New England Journal of Medicine, thus proposing that Fairchild may also be a chimera. A cervical smear test confirmed Lydia’s motherhood to her children.
6. Karen Keegan, USA:
In 2002, the New England Journal of Medicine published an article on chimerism. Karen Keegan, 52, was preparing for a kidney transplant to cure her kidney failure. She and her relatives did a histocompatibility test. The results confirmed that two of her three children are not hers.
Karen’s blood group was A positive with traces B. She was XX female \ female chimera; some of her tissues belong to her twin sister and some to hers. A biopsy from a thyroidectomy matched her children. Karen Keegan is an excellent example of immune tolerance; her lymphocytes could not attack the cells of her mother or her brother. Her case helped secure Lydia Fairchild’s motherhood.
5. Chris Long, USA:
Chris underwent a long-term bone marrow transplant to save his life. Three months later, his DNA in his blood had changed, but this is normal and the goal of the procedure. But after four years, he discovered that his lips and cheeks also contain DNA from his donor, even all of his semen begins to belong to his donor. He said, “I thought it was pretty amazing that he could disappear and someone else appears.”
4. Case of blood grouping Chimerism, Austria:
In 2005, the magazine Transfusion published the case of a healthy woman, her blood group is AB, while her father is group O. In science, an AB child can only generate for parents A and B, and for a father with blood group O, it is impossible to give a child AB.
The researcher performed a genetic search on the A, B, and O alleles found. Both alleles from the father were detected. The study concluded that the woman was a chimera with a fusion of half the AO genotype and half the BO genotype.
3. 4-year boy, China:
In 2011, the Journal of Forensic Science published a report on a chimerical child. A 4-year-old boy was to undergo surgery for hip dislocation. His blood grouping before the procedure showed it to be an AB group but in an atypical form. The blood of his parents was group AB and O. In science, parents AB and O will only have children A or B; the child’s results ruled out the paternity of his parents.
The scientists conducted further research and found that the boy has two ABO blood groups, one to be AO and the other to be BO genotype. The newspaper concluded that the boy was a chimera.
2. IVF chimera, USA:
IVF (In Vitro Fertilization) leads to a chimerical child, with male and female genitalia. In 1998, a group of scientists reported that, during an IVF procedure, 3 embryos were implanted in a 31-year-old woman. 36 days later, an ultrasound showed a single fetus. After birth, a child was investigated and confirmed to be a normal child. When the boy was 15 months old, he underwent surgical exploration. The procedure showed a sac with abnormal genitalia, the histological examination confirmed the presence of ovary, fallopian tubes, and uterus. The boy is chimera XX and XY. And this is the first reported case of chimerism after an IVF procedure.
1. 40 years old man, USA:
In 2010, Chimerism magazine reported on a case of microchimerism. A 40-year-old man with a condition similar to scleroderma (an autoimmune disease that affects the skin and internal organs), with a DNA test, female DNA was detected. The scientist believed that they could be maternal cells, but the test excluded this option. The only option left was that this DNA belonged to his missing twin sister. The scientist could not confirm the association of this microchimerism and his autoimmune disease.
E.O.E, earth:
Everyone else (E.O.E), including yourself, can be a chimera, naturally or acquired. Permanently or temporarily.
Pregnancy: Pregnant mothers have few fetal cells that escape into their bloodstream and then into various tissues. After delivery, the mother’s immune system will neutralize these cells. A mother was reported to have microchimerism from her child 50 years after her birth.
Filiation: The fetus will leave cells in its mother in the same way that the mother will leave cells in her children.
Siblings: maternal siblings may have traces of the other’s DNA, possibly handed over by their mother. The fraternal brothers will not share this.
Twins: In a scientific report, there is a higher probability of microchimerism and chimerism with twins, doubles, or triples. As mentioned above, 20-30% of all single births were originally multiple pregnancies with missing or absorbed twins.
Blood transfusion: This procedure includes the transfer of RBC red blood cells; As general information, red blood cells do not contain DNA, or nucleus to be precise. DNA in blood comes from immune cells. When blood is transferred, DNA is also transferred. It is temporary chimerism.
Bone Marrow Transplant – Some diseases require a bone marrow transplant, like Chris Long above, a permanent chimera will be spawned.
Organ transplantation: transplantation of other tissues also meets the criteria of a chimera, being an acquired permanent chimera.
Some features may indicate chimerism: Heterochromia (different eye colors) may indicate chimerism, but it is not a confirmatory sign. Two different skin colors can also signify chimerism (Tylor Muhl). Different colored patches of hair can be a sign of chimerism. All these signs cannot confirm chimerism; only DNA tests can do that.
