The study looked at a single letter change in our genetic code that affects the genes' ability to make proteins. Only rarely were the mutations harmful. Most of them were simply unnecessary
One out of 200 genes in the human genome can be turned off without any effect on our health. This is according to a study conducted by British scientists from the Sanger Institute and the Wellcome Trust. This study raised new questions about the effect of gene loss on our health and evolution.
The study looked at a single letter change in our genetic code that affects the genes' ability to make proteins. The researchers' findings showed that such mutations, while sometimes harmful, usually have very little effect on the individual carrying them, and it is possible that they may sometimes be beneficial in evolutionary terms.
The team studied variations in the genetic code in more than a thousand people all over the world. The researchers focused on a single letter change (referring, of course, to the letters of the genetic alphabet) (also known as SNP), which disrupts the proteins and leads to variations in which the resulting proteins are shorter or completely missing. Intuitively, one could expect that such a change - known as nonsense-SNP (nonsense mutations) would harm the person carrying it.
"We knew that these mutations exist and that many of them are associated with genetic diseases, but we were surprised to find out that they are so common in the general population" said Brindis Yingavadottir, the main researcher in the project. "We found that 167 genes can be turned off by these nonsense mutations, and that those people carry on average at least 46 variants of the gene. For 99 of these genes, both copies can disappear in an adult living a normal life."
Human DNA contains about 20 thousand genes: a full amount of 99 nonsense genes means that at least one out of 200 genes can be dispensed with. Some nonsense SNPs were also found among the 167 genes studied, eight of which are listed in the Human Genetic Mutation Database, which catalogs disease-causing mutations.
While the researchers found that switching off genes is generally a harmful action, there are exceptions. In East Asia, but nowhere else, there appears to be an advantage to losing the MAGEE2 gene.
"There is a theory that 'less is more' when it comes to genes" explains the research coordinator, Chris Tyler-Smith. "And we already knew about some examples of the advantage in the loss of a gene. However, this is the first time that a large-scale study of current human evolution has been carried out."
"The MAGEE2 gene is a new and interesting example, although we have no idea what this gene does, or why some people are sometimes fine without it. However, our study suggests that, overall, gene loss has not been an important evolutionary force. Our genome doesn't seem to be in a rush to get rid of these 'unnecessary' genes."
"Some types of genes tend to disappear. We found the greatest decrease in the genes that contribute to our sense of smell. It's possible that early humans didn't like smelly mates, so when humans started living in large groups, it helped their chances of finding true love if they couldn't smell their mate so strongly.
Genetic changes in the nonsense-SNP numbers were significant. The participants in the study had between 29 and 65 of these mutations each and therefore the difference between them was an average of 24 genes. 18 of the 169 nonsense-SNPs studied are also present in Craig Venter's genome published last year.
The research was funded by the Wellcome Trust.
to the notice of the researchers
Additional articles on the subject on the science website:
15 תגובות
fresh:
And in my opinion, the explanation I gave you in the discussion about the snakes, which is also the explanation I gave here in response 12 in the part discussing Hanan Sabat's words, proves that both of you are wrong.
Haha I meant to say that Hanan Sabat is right...
I think Haim Saban is right
It's amazing that just yesterday I had a discussion exactly the same as here in the article about snake poison
Hugin:
Although the description you gave is not what usually happens, here and there it does happen and it is precisely one of the mechanisms of evolution.
And in relation to Hanan's words - the very fact that evolution exists at all is because at any given time there are many variants of animals. If there was only the "perfect animal" evolution would have nothing to choose from to choose who would survive when circumstances change.
For example: there are commenters who write a lot of bullshit and they don't disappear
They even give themselves compliments by other commenters
And they are not extinct.
It is interesting that the article did not take into account that in the ways of natural reproduction mixed and opposite types of genome arrays are sometimes connected and the apparently 'nonsense' find a wonderful complement in the 'excess nonsensical' genome of the owner of the complementary array,,,
From such mixes, an incredibly 'selected' or 'excellent' genome often comes out.
(products of mixed marriages, for example,,).
Hanan,
What is the benefit of dark brown hair color over black hair color (in humans)? No benefit and no harm. Why is there polymorphism in this trait? Why did nature leave the dark brown hair color "in the field", even though it has no use?
Factors (genes/individuals/species) become extinct not because they are not useful, but because they are harmful (harm fitness). If there is no impairment of competence, there is no reason for extinction. Imagine you carry a gene that causes you to die at age 120, regardless of environmental factors. Up to this age, there is nothing preventing you from having offspring that will carry the gene on. There will be no choice of female partners against you because of this gene (no one will ever know about it, most likely). There is no preventing the gene from surviving, therefore it will not become extinct.
I agree with Michael and remind Hanan that unequivocally - there is no "unequivocal" in nature. Every rule has an exception and in this case I'm not even sure there is a rule at all.
To say that there is no nonsense in nature is like saying that everything is perfect in nature. Perfect, as we know, only exists when it comes to a divine, intelligent, holy and purposeful creation.
Greetings friends,
Ami Bachar
Diseases or defects are faults that nature tries to correct.
There are diseases that benefit certain populations (like sickle cell anemia in Africa). Serious genetic diseases, by their nature, lead to the death of the person who carries them, in the event that he does not receive treatment or lead to infertility or the inability to bear offspring. There are several diseases (such as chorea) that may be discovered at a late age and therefore people may pass them on to their offspring and continue the existence of the disease/trait.
In most cases, people born with genetic defects will not reach the stage of having offspring and the evolutionary mechanisms bring such cases to a dead end (ie extinction).
I do not agree with the statement that there are things in the biological systems that are neither useful nor harmful. Nature does not leave useless systems "in the field".
Hanan:
Your words are clearly not true.
There are many things in biological systems that are neither useful nor harmful. These are not extinct.
More than that - there are even harmful things (like certain recessive diseases) that survive.
Unequivocal -
1. There is no "nonsense" in nature.
2. There are no unnecessary things in nature (these disappear and become extinct quickly).
3. No unnecessary genes.
4. No JUNK DNA. (in the sense of redundant/junk DNA)
Nature does not create or maintain unnecessary structures. From the level of subatomic particles to the level of organisms. The laws of physics will not allow mechanisms that are ineffective and work against the equilibrium mechanisms to exist for a long time. All chaotic behavior works towards energy balance.
The only thing that can be said - we do not understand the genetic mechanisms enough to be able to make determinations. We are just at the beginning.
Hanan Sabat
http://WWW.EURA.ORG.IL
something that can easily be interpreted as nonsense,
When you can't understand him...
I will just warn:
Be careful when you call something unnecessary, especially when it's something biological.
Researchers have a great tendency to determine that things are unnecessary. For example, DNA itself was long considered an unnecessary organelle in the cell. And the appendix and tonsils were also considered unnecessary until recently.
In short, don't rush to conclusions
The same goes for Bibi and my son.
Good luck to both of them, but my heart is with Bibi and I hope that the Likud will succeed in taking the government
Nonsense mutations are not necessarily mutations that cause a transition from coding for an amino acid to coding for stopping synthesis. Single mutations in one nucleotide can cause a change in the amino acid that is interpreted from the sequence (although not always) and this affects the folding of the protein. A protein that does not fold as the cell expects it to fold will undergo elimination. There are some. It is not easy to eliminate them although too many mutations of this type will cause too great a loss of energy for the cell and then practical evolution will start to play a role. If you only have a few of these then... then that's a price the cell pays. Not always bad. Usually something the cell can handle. When he cannot withstand it - natural selection begins which will inevitably result in the elimination of the cell or the elimination of the error.
I think that saying nonsense is actually not a bad expression. Muttzit has no point is actually the one that is more sinful to the original in my opinion - because there is a point. Even if it is a codon that stops synthesis. That's his meaning. The product is nonsense and will undergo elimination - which will cause the cell to lose all the energy invested (the whole process protects the protein and destroys it).
Greetings friends,
Ami Bachar
The translation "nonsense mutation" is wrong with the original. A more appropriate translation is "uncompromising mutations". nonsense mutation - a mutation that changes a codon that is supposed to code for some amino acid, to a codon that instead codes for a stop in protein synthesis.