When I was a child, Greek mythologies were always my favorite bedtime stories. Among all the Gods, heroes and monsters, however, only one creature scared the hell out of me. Her name is chimera, a hybrid monster who has a lion's head, a goat's body, and a serpent's tail.
I dared not to listen to her story again. And at that time, I was just glad that this fire-breathing monster only existed in mythologies. But modern science said to me, human chimeras ARE walking among us.
A human chimera is someone who has two totally different sets of DNA inside the body. Well, this is not that scary like a fire-breathing monster, surely. But still, this is rare. How can someone have two different sets of DNA?
The creator of chimera
Does God create human chimeras? No, we all know he made us equal. The “god” of human chimeras is actually bone marrow transplant. The latest human chimera found by scientists is Chris Long, a man who had leukemia.
Recently, Long found that his DNA has changed to his donor’s after a bone marrow transplant. Three months after his lifesaving procedure, the DNA in Long’s blood has changed. Four years after the surgery, his lips, tongue, cheeks and even sperm have changed. He now has his own DNA only in his chest and head hair.
Why this will happen
As many probably know, blood cancer and other diseases may damage patients’ stem cells so that they cannot produce healthy blood cells. Their only hope is to find a matched donor and take a transplant surgery. Then, the healthy stem cells of the donor will replace the previous weak cells.
But this comes at a price.
The stem cells of the donor contain the donor's DNA. So, the produced blood cells also contain the donor’s DNA. As a result, the patient will have his own DNA in the majority of the cells and the donor's DNA in his blood, as is often the case.
What Long has experienced, however, is another story. He not only has the donor's DNA in his blood, but also has it in the majority of his cells. If you think twice, you may find the creepiest thing here.
Since Long has his donor’s DNA in his sperm, will he pass on the genes of his donor to his child? Unfortunately, we may never know the answer, as Long had already had a vasectomy. But experts say that this is impossible. "There shouldn’t be any way for someone to father someone else’s child," according to Dr. Andrew Rezvani from Stanford University Medical Center.
Even so, we have another problem. If the donor’s DNA was in a crime database and then the recipient commits a crime and leaves his DNA at the site, the donor may be identified as the criminal.
Due to Long’s case, more experts start to pay attention to bone marrow transplants and DNA. Before they work something out and set up a new regulation plan, you can just add it to the list of Tales of the Unusual. And there is one thing for sure: if you're planning to order a DNA profile, you’d better do it before a stem cell transplant.