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DNA Testing – Some history, mental illness, and chimeras

I researched information about DNA testing for a script I’ve been working on for some time. Part of writing requires research in order to fully develop a character. One of my characters is a twin, and the other is a chimera.

For about the last two decades, DNA testing is commonly used in forensics, paternity testing, and within the medical community. Before modern DNA testing was introduced in 1985 by Dr. Alec Jeffreys (Butler, 2005), the general public relied on blood typing in the 1920s, serological testing in the 1930s, and human leukocyte antigen (HLA) testing up until the early 1980s (History of DNA, n.d.) . Two different DNA testing techniques have been used since Dr. Jeffreys’ discovery, but the one used today uses polymerase chain reaction (PCR) technology, because it is more reliable, quicker, and less invasive than previous methods, claiming to be 99.99 percent accurate (DNA Testing Using PCR Technology, n.d.) in paternity testing. Modern DNA testing has revealed that there are links between family members with mental disorders, such as bipolar and schizophrenia (Boyles, 2009).

Despite the fact that DNA is almost considered “foolproof” by the United States government, there have been some incidences that prove otherwise, especially related to a condition called chimera.

Chimera has only been documented in approximately 40 people on earth (Weird or What, 2010). When a woman named Lydia Fairchild applied for state aid for her family, she was required to have DNA testing. After four tests determined that her husband was the biological father, but that she was not the biological mother of her own children, she had to endure the rigmarole of courts and humiliation, because she was accused of trying to defraud the state and having emotional issues. It was later determined that Lydia inherited two sets of DNA, which happens when two separate fertilized eggs fuse in the womb. Lydia was supposed to be a twin, but instead became her own twin – known as chimera (ABC Primetime, 2006).


Butler, Dr. John. (2005). Forensic DNA Typing: Biology, Technology, and Genetics of STR Markers (2nd Edition). Retrieved from:

DNA Diagnostics Center. (n.d.). History of DNA Testing. Retrieved from:

DNA Diagnostics Center. (n.d.). 1990s DNA Testing Using PCR Technology. Retrieved from:

Boyles, Salynn. (2009, January 15). Schizophrenia, Bipolar Disorder: Gene Link? Retrieved from:

ABC Primetime. (2006, August 15). She’s Her Own Twin. Retrieved from:

“Tetragametic Chimera.” Weird or What. (2010, June 9). (Video). Retrieved from: