Three months after his bone marrow transplant, Chris Long knew the DNA in his blood had changed. And Long knows who the DNA belongs to, a German man he has never met.
Four years ago, Long only exchanged messages with him. Later, the IT worker working for the Washoe County Police Department, USA received a transplant from a donor living 5,000 miles away.
A bone marrow transplant is designed to cope with Long’s acute leukemia, a form of blood cancer that prevents his body from producing healthy blood cells. It went smoothly. The damaged hematopoietic cells in Long’s marrow have been replaced by German men.
Theoretically, it is not surprising that they produce new blood cells, containing the DNA of the people they once belonged to. But the story has not ended there.
If Chris Long’s semen contains purely donor DNA, what happens when he has children?
Long only discovered his condition after being encouraged to have a blood test by a colleague at the Police Office. She has a vague idea of what might happen. Ultimately, the goal of a bone marrow transplant is to replace weak blood cells with healthy blood cells, including the DNA contained therein.
But four years after the operation saved Chris Long’s life, not only was his blood affected. His saliva and skin cells also contain donor DNA. Surprisingly, what surprised Long’s colleagues at the forensic lab was that his semen now also carried the donor’s entire DNA.
“I thought it was unbelievable, I myself disappeared and another person appeared in my body.“Long said. He became a chimera, a scientific term for people who carry more than one set of DNA on their bodies.
Chimera originated from Greek mythology, it is a three headed monster. Born in Asia Minor, the son of Typhon and Echidna. It is related to the Cerberus three-headed dog and the Hydra monster. Chimera has the body of a lion, but grows a goat’s head and a snake’s tail.
According to the Seattle Cancer Care Alliance, the term “Chimera“being used with the concept of mixed entities, referring to people who have had a heterozygous tissue transplant. A technique such as bone marrow transplantation, immature blood stem cells can grow into white blood cells, red blood cells and platelets in the recipient’s body, but they will carry the donor DNA.
Not only in myths and movies, do you believe that on this planet, right now, there are hundreds of thousands of people carrying 2 different DNA? In fact, every year in the US, tens of thousands of people get a bone marrow transplant. They are patients with leukemia, or have other blood diseases including leukemia, lymphoma and sickle cell anemia.
According to statistics up to 2013, the world has recorded 1 million bone marrow transplants, and one study found that nearly 50% of transplants will produce Chimera people.
The Chimera people caused all sorts of trouble, from the criminals escaping to the fact that their fathers were not their biological fathers. Lawmakers therefore had to put the bone marrow transplant factor into a special case in forensic medicine.
Although not everyone becomes a criminal after the transplant, the idea behind this phenomenon still stimulates Long’s forensic colleagues at Washoe County Police Department. Not to lose the opportunity, they turned Long into an experimental subject.
Doctors and many forensic scientists have long known that certain medical procedures will turn humans into Chimera, but exactly where the marrow donor DNA will appear in the recipient’s body – in addition to their blood? It is still a mystery rarely studied in terms of criminal science.
Chris Long’s case was presented at an international forensic science conference in September, but it has now gained the attention of DNA analysts outside Nevada.
Often a doctor doesn’t need to know where the donor DNA will appear in a patient’s body, because this type of chimera is not likely to cause harm. Chimera also cannot turn a person into someone completely different.
Andrew Rezvani, medical director of the Inpatient Blood & Bone Transplant Unit at Stanford University Medical Center, said: “The patient’s brain and personality will not change“He added that sometimes the patient would ask, if a man has a female chromosome in his blood or vice versa, what does it mean? Rezvani said:”It does not matter“.
But for a forensic scientist, Chimera is a different story. Assumption in a criminal investigation, when they gather evidence from the scene of a case. Each victim and each perpetrator could have left only one DNA.
But now, one of them can leave two DNA, one of his own, another of his donor, 10 years younger and living peacefully and honestly thousands of miles away. .
Realizing that this was a real problem, Renee Romero, who runs the Criminology Laboratory at the Washoe County Police Department, saw the opportunity as soon as Chris Long, her friend and colleague. find a suitable marrow donor.
“We need to gauze [thu thập] That damn thing [DNA] get out of his body before he does this procedure, to see DNA [người hiến tặng] will take over your body like“, Romero recalled what he told Long.
Of course, he agreed. Long felt ready to do anything that stopped him from thinking about his acute myeloid leukemia and myelodysplastic syndrome, both of which slow down the process of hematopoiesis, creating healthy blood cells.
At that time, he said, “I didn’t even know I could live [sau ca phẫu thuật] is not“.
But four years after the bone marrow transplant, Long is not only completely healthy, the disease has improved so he can return to work. Romero’s experiment also continues. At 4 months after the bone marrow transplant, she found that Long’s blood had been replaced by donor blood cells. Swabs from nah’s lips, cheeks, and tongue also showed another DNA.
Of all the samples collected, only DNA in Long’s chest hair and hair was affected. What surprised Romero’s team the most was that after 4 years, the DNA in Long’s sperm was completely replaced by the bone marrow donor DNA.
“We were very shocked when [DNA của] Chris is no longer present“, Said Darby Stienmetz, a criminologist at the Washoe County Sheriff’s Office.
Brittney Chilton, a criminologist at the Sheriff’s Department of Forensic Science, assumes that if another patient now responds similarly to a transplant, and then that person goes out into the crime, the DNA test results. may mislead the investigation.
And that’s exactly what happened, Chilton said in 2004, Alaska investigators uploaded a criminal DNA database in the United States of America with a sample of DNA extracted from field semen.
It coincides with a potential suspect. But there was a problem: This man was still in prison at the time of the attack. Examining the medical records, it turned out he had a bone marrow transplant.
The donor was his older brother who was later arrested and convicted.
Abirami Chidambaram, a researcher who works for Alaska’s Crime Detection Science Laboratory in Anchorage, who presented the Alaska case in 2005, said at the time that she had also heard about a script. causing another controversy.
In it, a victim claimed that she was sexually assaulted by a suspect, but DNA analysis showed up to 2 people. As it turned out, the second DNA came from the person who gave her bone marrow.
Yongbin Eom, a researcher at the Center for Human Identity, University of North Texas, added that similar scenarios could also create confusion around the victim’s identity. In 2008, Eom was trying to identify victims of a traffic accident for the National Forensic Agency in Seoul, South Korea.
Blood test results show that the victim is female. But the body seemed to say it was a male. The DNA in the kidney said that it was a male victim, but the spleen and lungs contained both male and female DNA. Eventually, Eom discovered the victim had a bone marrow transplant from his own daughter.
Returning to Chris Long, his situation poses an inevitable question: If his semen contains purely donor DNA, what happens when he has children? Will Long pass the genes of donors in Germany to children, grandchildren and future generations?
In this case, the answer was no answer, because Long had a vasectomy after the birth of the second child, before the time of his bone marrow transplant.
But what about the others? The three bone marrow transplant professionals surveyed agreed that it was an intriguing question. But they also agree that it is impossible for a transplant recipient to pass on the donor’s gene to their child.
“There is no way for someone to be the father of a child born to another person“, says Dr. Rezvani, medical director of Stanford University.
But the consensus on Long’s case could not prevent the confusing scenarios from happening around the Chimera people.
In 2015, an American man was concerned that his own child was not his own. The reason is, he shared DNA with his twin brother in the womb. His sperm only has 10% of his own DNA, the remaining 90% is the DNA of a twin brother who has never been born.
Because they were “oneness“Right from the womb, now the child born to this father only has a genetic overlap of about 25% for him, which is half the parent-child confirmation level. Intelligent-uncle relationship.
“But a blood cell donor cannot create new sperm cells“Dr. Rezvani said. Dr. Mehrdad Abedi, a doctor at the University of California, Davis, who directly treated Long also agreed:
He believes that it is vasectomy that explains why Long’s semen contains donor DNA. And forensic scientists say they will have to do more research to get a final answer.
All researchers who have considered Long’s case agree one thing: He is a living specimen worth investigating. It is not known if anyone else will respond to his bone marrow transplant surgery.
For his part, Chris Long said he hopes to meet the bone marrow donor for his upcoming trip to Germany. Long simply wanted to thank this man for saving his life.
Refer Nytimes, Futurism