Three months after a Nevada man received a bone marrow transplant, tests revealed the DNA in his blood had been replaced by the DNA of his donor, a man he barely knew, according to The New York Times.
Chris Long received a bone marrow transplant to treat acute myeloid leukemia and myelodysplastic syndromes. After the transplant, his colleague at the Washoe (Nev.) Sheriff's Office encouraged him to test his blood.
Swabs of Mr. Long's lips and cheeks contained both his DNA and that of his donor four years after the lifesaving procedure. All the DNA in his semen belonged to his donor. Of the samples obtained, only Mr. Long's chest and head hair were unaffected by the donor's DNA.
Mr. Long is a chimera, or a person with two sets of DNA. Experts know certain medical procedures can turn people into chimeras, but where exactly the donor's DNA will show up beyond blood is less certain.
Despite this gap in knowledge, experts believe it is impossible to pass on someone else's genes to offspring after a bone marrow transplant, according to the NYT. A donor's blood cells shouldn't be able to create new sperm cells, Andrew Rezvani, MD, inpatient medical director at Stanford (Calif.) University, told the NYT. Forensic scientists plan to investigate the topic further.
Physicians typically don't need to know exactly where a donor's DNA will present itself, because it is unlikely to harm or change a person. However, criminal justice cases carry the assumption that each victim and each perpetrator only have one identifying code, not two. If another transplant patient responded similarly and then committed a crime, it could mislead investigators, Brittney Chilton, a criminalist at the Washoe Sheriff's Office forensic science division, told the NYT.
Mr. Long's experience is unique, and it's impossible to determine how many other people would respond similarly to bone marrow transplants.