21st Century Necromancer

"So, you're saying..." Daimon Michiko, chewing on a perfectly grilled slice of beef tongue, listened to Chen Yu's summary: "The killer's DNA found on the deceased, after comparison, led to the arrest of someone with no alibi and no motive, is that right?"

"That's one way to put it, although I can't rule out the possibility that this person actually committed the crime and employed some method of operation that the police haven't discovered, with the so-called burglary and sexually motivated murder just being a diversion to confuse the investigation. But generally speaking, the current situation is that the person caught based on the DNA evidence at the scene is not the perpetrator," Chen Yu said, taking a sip of his drink.

"Sounds pretty strange indeed, but it's none of my business. The barbecue is more important!" Daimon Michiko tilted her head, thought for a bit, and realizing she had no clue, decisively turned her attention back to the barbecue on the table.

While eating, she also called out loudly to a waiter: "Excuse me, could we have another serving of diaphragm meat, thank you!"

Chen Yu didn't mind Daimon Michiko's reaction, it was just casual dinner conversation after all. Besides, other than barbecue and surgery, Daimon Michiko probably only showed interest in mahjong, hot springs, table tennis, and betting on horses—after all, she was Doctor X, known for her extraordinary surgical skills, so it was hard for her to think about such matters.

However, another person at the table was very interested in the topic.

Jounouchi Hiromi listened carefully to Chen Yu's words and after pondering for a while, asked him, "Mr. Chen Yu, is it possible to turn one person into another? Human cells can mutate due to environmental factors, right? Since human cells can mutate into cancer cells, could they potentially mutate into someone else's DNA?"

"From a probabilistic standpoint, such a possibility does exist, but in reality, it's absolutely impossible," Chen Yu shook his head in denial of Jounouchi Hiromi's speculation. "Cell mutations do occur in the human body, but these mutations are random and without specific order. It's like a monkey randomly hitting keys on a keyboard and typing out a sentence; while the probability exists, it's not realistic. It's merely a probabilistic concept."

"Moreover, even if a human cell could genuinely mutate into another person's DNA, it would just be a single cell. It's impossible to change all the DNA in one's body unless you replace every single cell," he added.

As he said this, Chen Yu suddenly paused, as if struck by a thought, and muttered involuntarily, "That's right, replace all the cells! How did I not think of that!"

"Is it really possible? To replace every single cell in a person's body, how can such a thing be done! If it could be done, then what method would you use to replace all the cells in a person's body?" Daimon Michiko's interest was piqued by Chen Yu's words, but she remained skeptical about the feasibility of such a feat.

Hearing Chen Yu's words, Jounouchi Hiromi also thought it unlikely, shaking her head in dismissal: "It's impossible, Mr. Chen Yu. You can't replace every cell in a human body."

"No, there is a method that exists," Chen Yu stated, his confusion now cleared, realizing what was actually happening: "From a medical standpoint, there is indeed a way to replace a person's DNA, to turn one person into another. It's just that this method is used for treating diseases. We haven't considered this angle, which is why we've fallen into a cognitive trap."

"What? There really is such a method?" Chen Yu's words immediately elicited exclamations of surprise from Daimon Michiko and Jounouchi Hiromi. Enjoy new adventures from My Virtual Library Empire

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"Is there really a method that can turn one person's DNA into another person's?" Inside UDI's office, Kube Rokuro was visibly astonished as he listened to Misumi Mikoto's explanation.

Misumi Mikoto put down her phone, her face also filled with astonishment. Although she had quickly grasped the situation after Chen Yu's phone call, without his reminder, she would not have been able to figure out the truth.

"I didn't expect it to be such a situation either. No wonder the master asked us to sample and test DNA from various parts of Yamada Yonegoro's body. If it's as you described, the presence of his DNA at the crime scene is not difficult to explain," Misumi Mikoto explained to Kube Rokuro. However, she still had one unresolved question: "But why is the master so certain that it's Yamada Yonegoro's DNA that has changed, and not someone else's?"

"That... Dr. Misumi, what exactly is the method Brother Yu talked about?" Kube Rokuro, seeing Misumi Mikoto deep in thought, quickly reminded her that she hadn't yet told him the exact method that could completely change a person's DNA to another's.

"It's a bone marrow transplant," Misumi Mikoto said, opening her computer and searching for related articles before continuing to explain to Kube Rokuro: "Human blood is produced by hematopoietic stem cells in the bone marrow, and the stem cell population is also an important entity that controls and maintains the regeneration of body cells.

In terms of function, stem cells have the potential for multidirectional differentiation and self-renewal, being the most primitive cells at the top of the cell lineage hierarchy. In the body, they can differentiate and produce cells of a particular tissue type."

"Therefore, once a person's hematopoietic stem cells are replaced, through the differentiation of stem cells, their body cells will gradually be substituted as metabolism progresses. Once all the cells throughout a person's body have been replaced, their DNA naturally becomes that of another person."

"It can really be done like that?" Rokuro was astounded. Though he had learned about hematopoietic stem cell transplantation as an important treatment for leukemia during his studies, he was unaware that it could change a person's DNA.

"But in that case, it's also possible that the murderer transplanted Yamada Yonegoro's hematopoietic stem cells, and the body's DNA was replaced with that of Yamada Yonegoro, right? Why do you say that it's Yamada Yonegoro's DNA that has been replaced, Misumi Mikoto?" Tokairin Yuko, now understanding the situation, shared the same confusion as Misumi Mikoto.

As both of them continued to feel puzzled, Misumi Mikoto's phone rang again.

She looked and saw it was a text message from Chen Yu, which read: "Yamada Yonegoro underwent a bone marrow transplant seven years ago, I'm looking into who the donor was."