Evolution does not stop for a moment, and it does not miss the human race either. Recently, a human mutation was discovered that spread in the population and is able to provide protection from a disease similar to mad cow disease.
Ever since man was human, he has relied on technology to improve his quality of life. In the last two hundred years, the era of vaccines began, a distinct bio-technological product that protects us from various diseases. But despite the attempt to break free from nature and its shackles, sometimes we find that the answer to certain diseases has already been found among the human population. And in at least one case, it seems that evolution can also find a solution for mad cow disease.
Twenty-five years ago, a blacksmith sacrificed her soul in England. An autopsy revealed that her brain was damaged and as if it was full of small holes, like a sponge. This was the beginning of the mad cow epidemic in Great Britain, also known by its scientific name ``bovine brain drain,'' which led to the destruction of more than four million cattle in England alone. Despite the determined action of the English Ministry of Agriculture, almost two hundred thousand cows were infected with the disease and approximately 165 people developed similar defects in their brains as a result of eating infected meat.
Although mad cow disease can be transmitted from animal to human, it differs from almost all other infectious diseases in that it does not rely on bacteria or viruses for transmission. The agent responsible for the transmission of the disease from patient to patient is a defective protein called prion. Proteins of this type are found in the brain, but their exact role there is still not fully known. We only know that in their normal state they are harmless, and contribute to normal brain activity. But when a damaged embryo reaches the brain, it is able to connect with the other normal embryos and pass them the same horrible change that it itself went through in turn. Those prions - now they are damaged themselves - take hold of other normal prions and distort them as well, and thus the number of damaged prions in the brain increases rapidly. The damaged proteins bind together and form insoluble deposits that are visible under the microscope as holes in the nerve tissue. The end result, inevitably, is death.
Mad cow disease is not limited to cows. The distorted prions of the cow are able to attack the human prions as well, spoiling them and turning them into ``zombie'' prions, which will attack other normal prions in the human brain. But there is also ``mad man's disease'', or ``kuru'', which is especially common among cannibal tribes living in the forests of Papua New Guinea.
The kuru disease is actually a variation of the mad cow disease, which almost wiped out the population of the eastern hills of Papua New Guinea in the middle of the twentieth century. The distorted prions responsible for the disease were passed from person to person at ceremonial funeral feasts held in honor of the dead. At these feasts, the women and children received a small piece of the deceased's brain on their plate, as a sign of the respect and mourning they had acquired for him. In this way, the prions could spread easily among the population, passing from the deceased to all his loved ones and relatives through the food. During the peak periods of the disease, more than two percent of the population died in the garden every year, and some villages lost almost all of their young women.
The idea of natural selection holds that in every population there are survivors who are better adapted to their environment than others, and therefore produce more offspring that carry their traits. In the Purusa Valley, located in Papua New Guinea, the living environment included kuro disease almost inevitably. Because of this, there is no wonder in the discovery that was published a few days ago, according to which some of the people in that area acquired a new and unique mutation capable of protecting them from the Koro disease.
This mutation, which has not been found anywhere else in the world, results in the creation of a new type of prion known as G127V in the human brain. The mutation was found in half of the women in the area who were supposed to be vulnerable to the disease, when it is present in both copies of the genes that code for the creation of the original and vulnerable fetus. A test conducted on the relatives of the families of the mutation carriers showed that it protects them to a significant extent, compared to families located in similar areas. The research, which began in 1996, was published on November 19, 2009 in the New England Journal of Medicine.
It is not yet clear how the mutant prion protects against the distorted prions. It is possible that he is immune to the harmful effect of the aggressive prions, or that he cancels their effect in another way that is not yet known. Whatever its operation, the discovery is particularly exciting because it demonstrates the operation of Darwinian evolution in real time in humans. Within a few decades - the time of a generation or two - the human population in the Purusa Valley developed a biological defense against a severe and painful epidemic.
It is clear that human evolution continues to progress, but at a difficult and painful price. In order for many in the population to be protected from the disease, many others - those who did not carry the gene that provides protection - had to die and avoid passing on their genes to future generations. But it is possible that the goat turned out sweet, because now scientists will be able to study the new mutant gene and try to imitate the way the protein that provides protection against the disease works. Ultimately, the vaccines of the future will be found out of the human evolution of the present.
More of the topic in Hayadan:
- Cannibalism was widespread in the world
- The madness of the cows and the mysteries of the fruits - Dr. Doron Lantz
- What is the source of mad cow disease?
For the article in the blog ofRoey Tsezana - a different science
Comments
The parallel to technological progress is a correct parallel. If you buy a regular car, and you're not a very good driver, one day you bang on the door and the next day the driver's door and so on until one day you find it has wings and the engine has become a jet engine and you can cross an ocean with it now, then that's probably evolution.
If you go under a particularly low bridge with your car and as a result its roof flies off and it becomes a cabriolet - that is not evolution.
Evolution for me is the creation of new genes and not the paralysis of existing genes. To claim that the accumulation of silent mutations on a gene, or on a random sequence, can eventually produce a new encoded or regulated gene is an argument that has never been proven. Statistically, it should have been proven a large number of times if you consider the number of genes that exist and have existed on Earth (a rate of tens of new ones every year, at least, for some reason we don't see it :))
Rah, understanding the exact mechanism is not always necessary and even contributes to understanding the entire process, sometimes a closer look contributes more to this. In the example here, the protein mapping can prove the change but does not necessarily contribute to its understanding. This is similar to understanding the operation of a computer: measuring and understanding the electrical signals on the bus ("bass") of the motherboard does not contribute as such to understanding the software code that runs on the computer. I want to say, the mutation changes that occurred in previous generations (tens and hundreds of generations) and did not harm until now, came to the fore when the soil was prepared for it, that is, when the conditions for their benefit were ripe. Until that moment their existence was not known.
Fascinating writing.
Yigal, everything you wrote is fine and dandy, except that such changes do not occur within two generations.
A, the mutation is mapped and the change is known. What is not clear is what the meaning of the change is, why the protein with the mutation does not undergo a change like a protein without the mutation.
It should be noted by the way that the difference between a harmful and non-harmful product is only structural, meaning that the sequence is the same but the folding of the protein is different. Presumably the mutation causes a situation where folding into the form of the harmful product does not occur.
In addition, it should be noted that to date the mechanism by which "bad" prions turn "good" ones into "bad" ones has not been found. If you simply mix the two types of proteins in a test tube, the above change does not happen, it only happens in living cells.
And by the way, the subject was also studied in Israel in the laboratories of Prof. Travolos and Gavizon in Hadassah.
Moshe, the intention was of course to 'apply' and not as I wrote in my previous response.
Moshe, not every change is evolutionary and it is indeed possible to contain the understanding of the mechanisms of evolution on mechanisms in different fields where this type of change also exists.
Eli and Rah, that mutations occur in all animal populations (including humans) all the time. If a mutation is harmful, it goes extinct. If it is useful in the conditions in which it appears, what good. If it is not harmful under these conditions (which happens in most cases) it exists in the population in a certain ratio that depends on the breeding ratio of the individuals. When a situation appears in which it is beneficial, the beneficial mutations (and I have no doubt that in this case there were several such mutations at the same time) begin to appear in the majority of the population until the stressful conditions that caused it disappear or until the mutation becomes dominant in the population. Such a phenomenon is called "leap evolution".
See the entry "Sickle Anemia". It is certainly possible that this is a simple point mutation.
Roy, there is indeed a problem with the calculation here. It is not possible that within a generation or two half the number of women contained the mutation on both alleles. Think about it, such a situation requires a founder effect such as the almost complete destruction of the population and its new creation from the resistant individual and this could not happen in two generations.
Presumably the mutation "hanged around" there for a long time and there was a very significant selection in its favor from the moment they started their strange mourning customs.
If within a generation or two of the appearance of the disease, a mutation can be discovered in part of the tribe's population (and not just in one family), this is a sign of one of two things: or the mutation is not so rare, and should be found in other populations as well. Or it is not random but is a reaction of the body towards the disease. In any case, the attempt to demonstrate evolution to the general public through short-term phenomena is doomed to failure in advance - because the strength of evolution is that rare changes of survival value that occur in a single ancestor will eventually make his descendants the majority in society. However, in a generation or two, it makes no sense that the proportion of people with a certain mutation in an area where it helps survival will be much greater than in areas where it is worthless, unless a catastrophe occurred that killed 99% of the residents of the area and this family is the only survivor, or almost the only one.
Your explanations and descriptions fit a lot of things.
You can paste the same descriptions for endless status changes.
Nothing makes it special except that the word "evolution" is your private mantra.
Like the word Om that some Indian meditation practitioners hum at every possible opportunity.
And really, the word 'evolution' means 'change', and is defined as a change in the percentage of individuals in a population that have a certain trait.
As in this case the protective feature against mad cow disease in humans was found, another feature could also have been found. All according to the constraints of the environment. When these changes accumulate, or when a particularly large change occurs, it is also possible to reach the creation of a new species within an existing population.
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My blog - Another science
In this approach, everything is evolution. Every change is an evolution, come on!