Sanqing headquarters, stem cell laboratory.
Ding Mian sat in front of the inverted microscope, staring at the camera with all his concentration, carefully examining the cell suspension in the glass culture dish, completely ignoring the continuous inquiries from behind him.
"how is everything?"
"Is there any result?"
"Hey, you should say something."
"Brother, please!"
"Just tell me a little bit, just a little bit."
Huang Qin kept pacing back and forth behind him, with a painful and tangled expression on his face, and pleading words kept coming out of his mouth.
Finally, his harassment was showing results.
"Successful." Ding Mian straightened up, stretched lazily, and said.
"Really?" Huang Qin stopped suddenly when he heard this, turned around, and couldn't wait to come forward: "Elaborate."
Ding Mian pointed to the microscope lens: "See for yourself."
Huang Qin put one eye in front of the camera, looked at it for a while, and said doubtfully.
"That's not right, the cells inside are completely dead."
Ding Mian waved his hand: "Look at the label. This is a mixed human-mouse stem cell fluid, the kind that has not been genetically modified."
Huang Qin suddenly realized it. He glanced at the glass petri dish on the experimental table and squinted for a long time before picking up a petri dish with the label "NF-kappa B-human mouse" and placed it on the inverted microscope. superior.
This time, within a few seconds, Huang Qin shouted excitedly.
"It's amazing, cell competition disappears."
"Our work is in the right direction. Turning off the NFKB gene pathway is indeed effective."
"These genetically modified human pluripotent stem cells can actually survive in a co-culture environment."
“The survival rate has been visibly improved!”
He turned back, his eyes flashing, and continued: "Does that mean we can do in vivo experiments?"
Ding Mian nodded with a smile: "It's ready."
Huang Qin instantly jumped up from his stool as if his butt was on fire.
"Then what are you waiting for? Let's do it quickly."
He was extremely excited at the moment. He felt that the door to the new world was opening a crack in front of him. As long as he squeezed hard, he would immediately enter the paradise he dreamed of.
After completing his doctoral defense at the end of last year, he returned directly to the company and worked with Ding Mian on the research and development project of xenogeneic organ transplantation.
The two conducted experiments for several months and finally made a qualitative breakthrough today.
At first, they tried to co-culture pluripotent stem cells from different species such as large-mouse (rodent), human-monkey (primate), human-pig and cow.
The number of surviving cells per square centimeter is then used as an indicator to determine the degree of cell apoptosis.
The answer is obvious.
From the third day, the gradual apoptosis of human pluripotent stem cells was observed in the culture dish, while the stem cells of other animals continued to grow.
On day 5, there are only a few survivors of human pluripotent stem cells.
This rate of apoptosis was so fast that they were immediately shocked.
They immediately compared the surviving human pluripotent stem cells with human pluripotent stem cells cultured alone to see what the differences were.
What is it that causes such fierce competition among cells?
After a round of genetic sequencing, the analysis showed that in the surviving human pluripotent stem cells, a signaling pathway called NF-kappa B was activated, which led to rapid cell apoptosis.
So, the next experiment was a matter of course.
The two plan to shut down this signaling pathway to test whether they can inhibit apoptosis in this way.
That's why today's scene happened.
The results were surprising. Human pluripotent stem cells after turning off the NFKB signaling pathway could survive in a co-culture environment.
In sharp contrast to previous experiments, cell competition between different species disappeared.
Regardless of whether it is human-mouse, human-pig, or human-cow, the stem cells of both parties become tender and affectionate in the culture dish, as close as a family.
Of course, humans and monkeys belong to the same species, and the competitiveness of stem cells between the two is similar. There is no obvious cell competition phenomenon, and they are mainly used for comparison in experiments.
As for the other three species, due to the considerable evolutionary distance between species, there was originally intense cell competition.
Stem cells from mice, pigs and cows, which are at the front of the evolutionary tree, are relatively competitive and will quickly induce apoptosis in less competitive human stem cells.
Cell competition is originally a ubiquitous biological phenomenon and is a normal result of natural evolution. It is mainly to prevent the invasion of foreign cells and is very similar to the principle of the immune system.
However, with the support of human beings' powerful genetic technology, this mechanism quickly collapsed, creating the miracle of harmonious coexistence of stem cells of heterogeneous organisms.
Seeing a breakthrough in their research, the two were overjoyed and immediately started a new round of in vivo animal experiments.
Pigs and cows are too big and have too long gestation period, so we should start with human-mouse heterogeneous chimerism to test the new research and development results.
Chimeras are mostly prepared by microinjection, that is, human pluripotent stem cells are injected into early embryos of mice through micromanipulation.
Of course, the human pluripotent stem cells here have been genetically modified to turn off the gene signaling pathways that lead to cell apoptosis.
Five days later, the embryo had 250 cells and successfully developed into a blastocyst.
In the next 15 days, the chance of chimerism was greatly improved, and the embryo was successfully formed in the mother's body.
Seeing how smoothly human cells and mouse cells fused, Huang Qin couldn't help but feel worried.
"Well, if a human-mouse chimera is really born, there won't be any ethical issues, right?"
Ding Mian asked: "What ethical issues will there be?"
Huang Qin thought for a while and hesitated: "Won't human cells affect the mouse's reproductive cells?"
Ding Mian gave him a strange look and said casually: "You have to worry, just wait until the mice are born and castrate them."
Huang Qin blushed and said, "That's not what I meant. What I meant was, will human genes affect mice? For example, will there be genetic mutations in the brain?"
"Don't countries like Eagle Country have ethical requirements for human-animal chimeras? They require that they not have the ability to reproduce, and they cannot develop into a brain."
"You also know that the biggest difference between humans and animals is brain development. If the mouse brain develops for the second time, is it really okay?"
Afterwards, deep worry appeared on his face.
"Hey, so that's what you're worried about." Ding Mian smiled and said, "It's okay, it's just a few human stem cells. Even if they are distributed in mice, there won't be too many human cells in each part."
"As for the brain problem, that is even more of a ridiculous worry. Even if human brain cells are in the brain of a mouse, they can only do what mice should do. It will not have human thoughts."
"Because what makes humans human is determined by the structure of the brain, not by individual cells."
"You are a biology student after all, so you can't even figure this out."
Huang Qin was stunned: "But I'm still a little worried. My wife and I reviewed the classic film Rise of the Planet of the Apes two days ago, and I feel that the plot development in it still has a certain scientific basis."
Ding Mian said angrily: "You are suffering from the sequelae of watching the movie, don't think about it. They are gorillas. They are the same species as humans. Their genes are 99% similar and their brains are also very developed. Of course they will." It may have mutated."
"You know, early Homo sapiens also had many competitors on the earth. For example, the Neanderthals were a serious enemy."
"Neanderthals were physically stronger and had larger brain capacity than Homo sapiens. They also shared 99.7% of their DNA with Homo sapiens. Overall, they even had a slight advantage."
"But they were eventually defeated by Homo sapiens."
"Do you know the reason?"
Huang Qin said nonchalantly: "I know, I've heard about it vaguely. It seems that a paper in Science mentioned it a few years ago."
"That's right," Ding Mian rushed to reply: "It's good that you know."
"The main reason is that a gene called TKTL1 in Homo sapiens stands out and undergoes an important genetic mutation, which encodes a new amino acid and synthesizes a brand new protein in the body."
"This protein is produced when the fetal brain is first developing and drives the formation of neuron cells, allowing humans to have denser and longer neurons, particularly in the neocortical region."
"The neocortex is mainly involved in high-level functions of the brain, such as spatial cognition, sensory cognition, language, logical reasoning, motor instructions, etc."
"In this way, no matter how large the brain capacity of Neanderthals was, it was still a low-end version that could only complete some basic functions."
"But Homo sapiens is different. Relying on genetic mutations, they have unlocked language abilities and collective functions. The size of the group can exceed the upper limit of dozens of people, forming an organization of hundreds or even thousands of people, and then gradually become the overlord of the earth. "
"A small genetic mutation, a change in the amino acid structure, and the formation of a new protein completely changed the destiny of the Homo sapiens race and created a great civilization."
Ding Mian couldn't help but sigh: "Nature is so magical, and the birth process of life and civilization is so incredible. Every time I think about it, I am filled with emotion."
Then, he looked solemn and said.
"Because of this, if similar genetic mutations occur in gorillas or apes, it is very likely that the brain will develop again and catch up with human intelligence."
"That's why the ethics committee strictly restricts our genetic modification of primates. As long as we don't act recklessly, there should be no problems."
"As for other animals, their genomes are too different from those of humans to have an impact on the brain, so don't worry."
However, these words did not completely eliminate the worry in Huang Qin's eyes.
But he did not continue the topic, but nodded and agreed with Ding Mian's conclusion.
"I understand that science fiction movies are fiction and belong to artistic creation."
"As long as we don't conduct genetic experiments on primates and don't give our distant relatives the opportunity to overtake in detours, the plot in the movie won't happen."
"This is why we insist on transplanting pig organs."
Ding Mian waved his hand with determination and made a slashing motion, showing a murderous aura.
"That's right, even if you do it, you won't be able to allow the embryo to survive for more than a month. You must completely kill the threat in the womb."
At this time, in the cage behind them, the female rat suddenly made a shrill squeaking sound, interrupting the conversation between the two.
Ding Mian trembled all over, slowly turned his head to look over, and opened his mouth in surprise: "Ah, she's about to give birth."
Huang Qin said hurriedly: "Let's go and have a look. I don't know if this chimera can survive."
The two hurried over and looked curiously at several pink and white meat balls emerging from under the mother rat's body.
"Leave it to fate, we can't help much with breastfeeding." Ding Mian shrugged and said.
Huang Qin counted the meatballs and found that there were five. His expression suddenly changed: "They all survived, not one of them died. The survival rate is 100%. It's really scary."
Another question flashed through his mind: "Tell me when we will euthanize them."
"What? Are you still thinking about this nonsense?" Ding Mian was stunned for a moment, and then he realized it and said in surprise: "This chimera doesn't look like it will die."
"Are you thinking too much? The lifespan of mice is only one or two years, and this kind of chimera cannot live long. Are you still afraid that it will live too long?"
Huang Qin stared closely at the little ones lying on the belly of the mother rat, drinking milk with their eyes closed, feeling vaguely uneasy.
"I'm not worried. The main thing is to go through the process. Originally, this chimera will also be destroyed. I'll feel better if I finish it earlier."
"Otherwise, it always makes me feel creepy to think that this mouse has my cells in it."
Ding Mian closed his eyes, took a deep breath, opened his eyes again, and said calmly.
"Okay, then follow the procedure and destroy it after four weeks. I don't know if these little guys can survive until then."
"Anyway, I won't use your cells next time. I'll use my own, so you won't find anything weird anymore."
Huang Qin smiled awkwardly and hurriedly explained: "Listen to me, that's not what I meant. I just have a bit of obsessive-compulsive disorder. Didn't I do animal experiments before? I have never used my own cells, so I am a little uncomfortable."
Ding Mian said speechlessly: "You are simply Ye Gonghaolong. Who first told me that such a big project requires a sense of participation, so your cells should be used?"
Huang Qin scratched his head, feeling a little ashamed, and his voice lowered.
"This guy is like this. When I haven't seen him before, he always wants to try it. But when he actually tries it, he feels like he can't stand it, haha."
But the next few words he said made Ding Mian want to run away.
"Xiao Ding, what about the human-pig chimera? Wouldn't it be weird if you used your own cells?"
"Think about it, when the pig has your cells and looks at you in the cage, can you withstand it?"
"The genes of pigs and humans are also very similar. Add in your own human genes, tsk tsk, I can't even imagine this scenario."
"Shut up!" Ding Mian said two words expressionlessly.
Huang Qin opened his eyes wide in surprise: "Xiao Ding, no, why are you still angry? I just said that casually."
"You!" Ding Mian finally lost control of his emotional control and turned around and left angrily.
