Gene therapy has enabled adult monkeys, who were color blind from birth, to have vision based on three colors. The experiment points to the incredible flexibility of the brain, which can adapt to completely new signals even at a late stage in development
Color blindness is very common in humans. About one in every 12 men and one in 230 women have this symptom. The inability to distinguish between red and green is the most common type, and it is caused by a mutation in one of the visual pigments - the proteins responsible for absorbing light in a certain wavelength range.
In a new study, scientists used gene therapy to insert a normal gene that codes for the creation of a visual pigment that picks up the long ("red") wavelengths into the eyes of two squirrel monkeys, which naturally lack this gene. The cells in the monkeys' eyes expressed the gene - and what's more surprising, the monkeys were able to decode the information and see colors they were unable to see before.
The couple Jay and Maureen Neitz from the University of Washington in Seattle, USA, led the research published in the weekly Nature. In the retina of squirrel monkeys, like that of color-blind people, there are two types of photoreceptors (photoreceptors, light-sensing cells, which operate at relatively high light intensities, and allow color discrimination): those that produce a visual pigment that absorbs short wavelengths (blue), and those that produce color Vision that absorbs medium wavelengths (green).
The researchers injected transgenic viruses into the retina, which injected the gene for the red light-absorbing visual pigment into the cells. The gene was designed to be expressed only in the light-receiving cells that naturally received green light. Thus three types of cells were created: blue light receptors, green light receptors, and cells with two types of proteins, green light receptors and red light receptors.
Four months after the injection, the researchers found that some cells in the retina do respond - that is, transmit a nerve signal - when they absorb long wavelengths. But this is the easy part - the gene was inserted into the cell and the protein worked. The big question was, will the monkeys' brains be able to correctly decode the signals, and give the monkeys true trichromatic vision (based on three colors)?
The accepted assumption among neurologists was that at a very early stage after birth the brain learns to decode the signals coming from the retina, and any changes made after that cannot affect the way the brain works, and therefore the way the monkey perceives colors. Both monkeys were adults, well past the critical period, but the researchers felt they had to try anyway.
The monkeys were trained to touch color spots on a touch screen. The color-blind monkeys easily recognized blue and yellow spots, but had difficulty distinguishing between the green and red spots and the gray background. In an interview with the Nature podcast, Neitz said that the monkeys seemed frustrated when they failed to complete the task, and angrily shook the computer screen. 20 weeks after the injection, they improved dramatically in recognizing these spots, indicating that their brains correctly decoded the signals sent to it by the cells expressing the new gene. "They looked much happier," Neitz said. Two years after the experiment, the two monkeys still see colors, and they did not suffer any side effects.
The experiment indicates The incredible flexibility of the brain, which can adapt to completely new signals even at a late stage in development. And of course, the research gives hope to the color blind among the human race, and to people whose vision is damaged in some other way - gene therapy may be the answer.
By Yonat Ashchar and Noam Levitan. Published in the December issue of "Galileo" magazine.
19 תגובות
Doron, try the "Space and Satellites" forum in the forums of the Tafoz site.
I have no choice, but I must ask at this time and in this place, where is there a place where I can ask questions related to science, in particular regarding the earth and outer space, I have many questions and I am sure there are clear and simple answers to them, but I do not know them, thank you from the bottom of my heart To anyone who will help me.
Yair, as one of those 8% myself, I think you accurately described the phenomenon.
Year:
There are certainly all kinds of possible reasons for color blindness, but I think that even if it was possible to accept your words before reading the current article, then the research described in the current article, in which the problem is solved precisely by "correcting" that one mutation, confirms the research assumption that, at least in the animals tested - This mutation was the cause and disproves, regarding these animals, your theory.
A note on color blindness: the article opens with the famous note that about 8% of men are color blind. The phenomenon is explained "the inability to distinguish between red and green is the most common type, and it is caused by a mutation in one of the colors of vision".
Since I have this phenomenon, I explored it on a perceptual level through my eyes and through the eyes of others.
The first time I was told I was color blind was when I was recruiting for the army. Several years later I realized for the first time that I had difficulty seeing colors when in a group of scouts one commented that she recognized Yitzchak by the red shirt, which I could not recognize, even though my distance vision was a hawk.
To summarize, the fact that the subjects of the phenomenon are unaware of the problem should have warned doctors and scientists against using the populist and stupid term color blindness.
The vast majority of the 8 percent are not color blind at all. They notice all the colors and all the shades!
The problem appears in a complex color environment. A good example is a green field where there are few anemones. The chance that in this environment I will notice while driving through the shops is small.
However, from the moment I noticed the baskets again, I have no difficulty distinguishing them with additional glances. Those with the phenomenon have no difficulty distinguishing the shades of red in a green field while walking. But when the distance increases, the difficulty resumes.
Similarly, the purple may be indistinguishable, under the conditions of a certain colored environment. Also, due to certain failures in color distinctions in the past, the carrier may produce a kind of shock absorption in the color definition, which will lead to defining a certain shade of green as gray and another as brown. Most shades of green will not lead to any mistake.
According to these abbreviated statements, the explanation that the phenomenon is caused by a mutation in one of the eye colors is exaggerated, meaning that there are other factors involved besides the genetic difference, and there is probably more than a single mutation structure.
jubilee:
Good that you clarified your words.
To be honest - if I understand correctly, you never claimed to know that the sawing is not performed under general anesthesia, but you simply referred to such a claim that was presented at the hearing.
By the way - the shocking video you saw - I also saw it and it is indeed terrible and terrible, but in my opinion there is no room for comparison between it and animal experiments - neither in purpose nor in quantities.
Lest it be misunderstood, I am not claiming that such cruel things do happen in laboratories in Israel or in the world, but I vaguely remember several articles from the past few years in which harsh claims were made in this regard regarding cruelty to animals in various research laboratories, as I have no real way to go and check if these things Really true or not, I can only hope that these are just stories and nothing more, overall this research is very important, but we also have to consider the poor animals that "give their bodies" for these experiments.
As I said, I also think it's cruel.
I was just trying to explain what is cruel about it.
People are also required to sign when they enter a hospital - not for an experiment but for treatment.
I tried to clarify one thing (and if someone argues with this - he will recover and not start answering as if I said it was not cruel) and that is that inserting electrodes into the brain is not painful. I think it's interesting information that it's a shame that they try to overshadow it.
It is also important to know that, contrary to what has been said here, there are no experiments that involve sawing the brain.
In addition to this - it is hard for me to believe that the sawing of the skull is not performed under anesthesia - in my opinion it is forbidden to accuse someone of such an accusation without an examination. Has anyone among those who claimed so looked into the matter? If not - (because it's better late than never) I would expect whoever said this to look into it and, if necessary, also apologize.
Yuval, you are right. And I also saw the horrible video about the skinning of the animals in China while they were alive. But past experience shows that the more we progress and the more countries develop and become more enlightened, the more laws are enacted for animal rights. Therefore, I think there is still hope.
Yael, I have indeed heard of such cruel experiments in the past, do you know why sawing the brain, which must be an operation that causes enormous pain and suffering to the animal, is not done under general anesthesia? Is this due to any technical or scientific constraints related to the experiment? Or is this only due to the cruelty of the scientists who perform such experiments and do not care about the great suffering they cause the animal?
A few years ago, I saw a particularly cruel video about animals being stripped of their skin and fur while they are still alive and when they scream in pain, the explanation I read for this cruel action was the dumbest explanation imaginable, I think it was done in China, and many of the Chinese who eat these animals believe that as The more the animal is in pain before it dies, the tastier its meat is. What a twisted thought, even if it was true, does it really justify such a monstrous action? Some people don't deserve to be called human.
It is true that such experiments are also done on humans, but with one small difference (besides the sedatives and anesthesia) - that humans sign before the operation that they agree to have an experiment performed on their bodies, while these poor animals are born into a cage, live their whole lives in misery, and then open They have the brain, without them signing and agreeing to it.
It is indeed cruel but it is worth noting that the brain itself has no sensation of pain.
Experiments of this type (on a much smaller scale) are also done in humans undergoing brain surgery.
They are awake, cooperative and do not suffer.
It is true that their skulls are not opened just like that and they are not fixed in place for weeks, but you should know that this is the cruel act and not the insertion of the electrodes into the brain.
Yuval, does that seem cruel to you? There are laboratories in Israel (I don't remember exactly which universities) that fixed monkeys so that they could not move, then sawed off their skulls and inserted electrodes into their brains - and all this, while they were alive and feeling everything.
This is how they are left awake for weeks without anesthesia with half their brain outside, to research and do neuroscience experiments.
I can only hope that when they injected the stuff into the monkeys eyes they did it while they were sedated, a needle being inserted into the eye is one of the most shocking and painful things I can think of, it gives me chills just thinking about it.
I read this article several years ago, it's a material cycle.
A fascinating course on the brain on behalf of the Hebrew University:
http://www.youtube.com/view_play_list?p=D8C99F67C81778E8
age,
1. There is no such thing as 4/5/6 primary colors but only three - man blue green. From the connection between them you get the rest of the colors you know.
2. Certain snakes have the ability to distinguish wavelengths in the infrared range (distinguishing the body heat of a mouse/next meal).
3. "When you came out"? You must have meant a little
4. These viruses were genetically engineered so that they were left with the ability to "infect" but what they transmit in the infection process is not what they originally knew how to transmit but only the specific gene that the researchers wanted to plant in the retinal cells. It is the utilization of the "good"/desirable abilities of the viruses after their destructive abilities have been removed from them. Or in other words - castrate them and then equip them with something else.
If you find a gene responsible for this…
It could be interesting 😀
And what will happen if we add more primary colors to 4, 5 or 6 primary colors including wavelengths that are not in the visible range at all.
Playing with viruses is extremely dangerous, if these viruses are contagious it will affect the entire population, including the possibility of infection to other species.