Donor DNA Detected in Semen of Bone Marrow Transplant Recipient

To treat his Acute Myeloid Leukaemia, Chris Long, an employee of the Washoe County Sheriff's Department, underwent a bone marrow transplant.

While the treatment was successful, he found after testing that his semen contained only DNA belonging to his donor.

Bone marrow transplants are designed to replace existing blood cells and stem cells, and as such, chimerism is expected in blood and bone marrow. The story has also generated some concern about the presence of donor DNA in sperm; however Long has had a vasectomy -- meaning that the analyzed samples do not contain sperm. The donor's DNA was likely found in the other cells contained in semen, such as leukocytes. This does not mean the patient could father a child with the donor's DNA.

This finding does carry implications for forensics which relies on each person carrying and leaving behind one sequence of DNA, not two. This could mislead investigators searching for perpetrators of crimes.

As for Chris Long, he told reporters that he hopes to meet his donor when he visits Germany so that he could thank him for saving his life.