Itoero

@OP,

 

E. coli is ordinarily a haploid organism; therefore, it has no need of any mechanism to make one allele silent. Yet it can be made partially diploid by using plasmids. The gene for the lactose repressor protein is sometimes given the symbol i. Most lactose repressor mutants coding for a nonfunctional repressor i^- are recessive to the wild type form i⁺. A few mutants that code for a nonfunctional repressor, however, and dominant, i^-d. How do you explain these two observations?

-A haploid organism has no need for a mechanism to mask an allele but haploid organisms use RNA polymerase, just like diploid organisms. RNA polymerase has the ability to chose between 1 or 2 alleles, regardless in which organism it's used.

-Maybe they are codominant?

We are made to die...it allows us to adapt to a changing environment.

If we find everything in our DNA which limits our lifespan then maybe we can cut and paste in our DNA until we can live forever.

My favorite books are the ones of Tolkien and Conn Iggulden (3 books about Genghis Khan)

I hope the Silmarillion will ever be used to make a TV-show.

It may be approved but you aren't receiving properly assayed medicine; it could be any purity and anything. A neuropathy is too serious to contemplate self-medicating.

I doubt it will be cleared, it's in the customs for 7 weeks now.

If it arrives then I will compare it with idebenone from a known brand, under a microscope.

It's a yellow/orange crystalline powder.

I have a digital microscope with max magnification of 300. I hope that will suffice.

Except in this case, where the explanation does in fact explain exactly what causes it. You're just ignoring the explanation.

That's not true.

Again, describing a dominant relationship does not explain what causes the relationship.

Many recessive alleles are just as functional as dominant alleles. Those recessive alleles must be blocked which is only possible if there is a chemical difference between dominant and recessive alleles, noticeable by RNA polymerase/mRNA.

A small RNA encoded by the first allele recognises a specific sequence on the second allele and blocks its expression. It's explained on this website: http://www.inra.fr/en/Scientists-Students/Mechanisms-of-living-organisms/All-reports/Understanding-the-mechanism-behind-dominant-and-recessive-gene-expression/Chapter-Three-Back-to-evolution/(key)/2

 

 

RNA polymerase binds to promotor DNA and separates the double helix.

It then adds complementary RNA nucleotides at the correct allele. This is the start of mRNA.

A ribosome translates mRNA to an amino acid chain (protein)

 

This process is the main cause for the dominant relationship between alleles.

 

When I asked for the cause, I asked why mRNA is formed at the correct allele.

It seems that RNA polymerase forms mRNA at the correct allele by the presence of sRNA or RNA targets on the allele.

I'm a miserable little shit. You just have to ignore me. It looks like most everyone did. I'm glad.

Do you want to be my friend? I'm a miserable little shit as well!

Asking why something would not happen in a certain way is starting out on the wrong track. The question is what does or does not happen, based on evidence.

A small RNA encoded by the first allele recognises a specific sequence on the second allele and blocks its expression.

http://www.inra.fr/en/Scientists-Students/Mechanisms-of-living-organisms/All-reports/Understanding-the-mechanism-behind-dominant-and-recessive-gene-expression

I wasn't wrong, was I? I think it's bad manners, dishonest and just plain annoying for someone to apparently ask a question, as though they wish to learn something, then argue that the answers are wrong as the discussion proceeds.

I asked the cause for dominance/recessiveness and found it myself.

And explaining how alleles behave dominant does not explain what causes it.

Because you ignore my answers and questions. Asking the wrong questions won't help you understand the principles. Last try: to you understand the difference between gene and gene product?

Yes I do. I asked those questions because you are imo wrong.

In your example proteins decoded by alleles of the same gene modify each other's function.

The modification of proteins is a property of genes working together, not alleles in a gene. It's called post-translational modification.

I cannot help you if you just ignore the bulk of biological required to understand the process. Not understanding proteins is not understanding what a gene is. I do not sense any effort on your side to understand the process therefore I opt to not further waste my time.

Why do you refuse to answer my questions?

Itoero,

 

I think that you are misconstruing the meaning of the word "mask." For one thing to mask something else does not necessarily mean that there has to be a direct interaction between the two things.

There is a way a dominant allele can block a recessive allele, so why wouldn't that be used in most genes?

You are still not getting it. Both alleles can express proteins (do you understand what a protein is and how it relates to a gene? If not, ask or look up, it is crucial for understanding). The proteins differ in sequence (as alleles may have different sequences). Different amino acid sequences can alter the function of the protein. This is the part that does not require additional regulatory control to explain dominance.

Can you plz answer my questions?

 

*Do a and c modify the function of b? I thought this was only possible between genes and not alleles of a gene.

 

*A recessive allele is masked by a dominant allele in a gene.

This is visible in the alleles which cause our blood type, alleles which cause the colors of mammals, alleles which cause diseases...

Do you deny this?

 

*This is the Wikipedia definition:

"Dominance in genetics is a relationship between alleles of one gene, in which the effect on phenotype of one allele masks the contribution of a second allele at the same l"

This is wrong in your opinion?

Why should a recessive allele be blocked in the first place? You are aware that in almost all the posts before we discussed how it is in a non-regulatory situation? If you still think that dominance is specifically a mechanisms that prevents expression of a recessive allele by the dominant one, then your model is flawed. The description is based on phenotype and the interaction can be simple. Examples were given above example (i.e. protein activity, did you understand that part or was that unclear) or due to regulatory influences, that may involve interactions with other gene products. These includes often transcription factors, though the role of small RNAs is getting more and more attention.

 

If you are really confused how gene regulation works, I would first look into transcription factors, which is a more canonical view as basis. Then expand into regulatory RNAs. I do feel that you may have quite some ground to cover in order to understand the elements and their interaction.

A dominant allele masks the contribution of a recessive allele on a phenotype. Since dominant alleles can block recessive alleles with sRNA, isn't it logic that most dominant alleles use that?

I don't know the exact system, but I'm not confused.

A recessive allele is masked by a dominant allele in a gene.

This is visible in the alleles which cause are blood type and alleles which cause the colors of mammals.

 

The simplest case is if an allele results in the loss or reduced function of the protein it codes for. Let's call the allele a and the phenotype p-. If an individual has two of this allele (aa) the individual has not functioning protein and the phenotype is p-. However, if he is heterozygote and carries a functional version (b) in addition to a, the functional one may be sufficient to cover the deficit, hence ab would be p+. Then there may be a third allele, c, which is functional, but not quite as efficient as b. If you have got cc, you have phenotype somewhere between p+ and p-, let's call it p+/-. So if you got bc, you got p+, as the more efficient b covers c. Thus b is dominant over a and c. But if you have ac, the somewhat functional c covers the deficit of a and you may have p+/-.

Do a and c modify the function of b? I thought this was only possible between genes and not alleles of a gene.

thx, I did not look in that column...pretty stupid of me.

 

Idebenone is approved for the treatment of Leber’s hereditary optic neuropathy...a degeneration of retinal ganglion cells.

Two days ago I had an appointment with my ophthalmologist and he saw damage on my optic nerve which partially exists out of retinal ganglion cells.

I suppose I can just ask a doctor for a prescription for idebenone.(raxone)

Were you unable to find this page?

https://en.wikipedia.org/wiki/Idebenone

No but it's never said idebenone is on prescription.

Sigh. Really? A recessive gene does not need to be prevented from expression. In fact, some better known examples work on the protein level. For example due to different level of functionality.

I meant to ask: 'What else can block a recessive allele?'

I suppose you mean something like a modifier gene?

There is a dominance-based relationship between the alleles of a modifier gene.

When you don't know the ropes it doesn't seem odd to ask where ones target audience, that might know something, may possibly hang out and give advice. It seems a reasonable first step.

I would do it differently but what you say is very true.

I also believe that Raxone (which has idebenone as sole active ingredient tbomk) is prescription only in Europe. This is probably why European based customs is checking up on the import of a restricted (ie restricted to medical prescription) substance into the EU and around the EU. Remember that the EU operates with a single border - it is where it lands into the EU where the european based checking is done rather than the domicile of the end user (where you might get more local checking)

Damn that's true.

I did order capsuled idebenone from the uk, I'm curious if that will arrive.

It's strange that idebenone is on prescription.

It's strange to ask this on a forum.

I see plenty of prescription drugs on sale on-line.

However , wiki says the stuff is prescription only.

Can you quote or link the page that says idebenone is only on prescription?

Known webshops like smartpowders and powdercity sell idebenone in high quantity.

is it possible that we should not classify humans as animals; because they have a natural better understanding of the world in the bigger picture? I dont know how hominids thought but i think even they question their existence and in almost any circumstance create tools and lead to doing science. I think science is the main way we advance. we do experiments and observe the world. so is it possible to put humans in a different category because of the fact that they are mentally too different? maybe this just comes from the fact that I hate when people call humans animals. it makes it seem like we have not evolved, but i am always amazed of how evolved we actually are and how much better we have become from creating fire, how much we can create now.

If we are not animals then what are we? We share countless biological systems with other animals...even with plants. I think it's odd to distinguish us from animals.

They do not even have to be expressed. Sometimes a phenotype (on which selection works) is there because a gene is not expressed. Also note that sRNA regulation is a special case and using that to understand the general mechanisms of dominance is a bit like trying to understand extrapolate energy metabolism by looking at phosphorylation of glucose.

Why do you think that's a special case? What else can block a recessive gene?

The simplest situation of dominant and recessive alleles is if one allele makes a broken protein. When this happens, the working protein is usually dominant. The broken protein doesn't do anything, so the working protein wins out.

This is just an explanation of a dominant relationship between alleles...that does not say anything about the cause for the relationship.

Then the dominant gene would likely be quickly weeded out of the gene pool because every carrier of it would be made less fit. Constrasted a recessive phenotype that is less fit, where someone with a single copy of the gene generally does not negatively impact the fitness of the carrier and as such those genes tend to persist in populations in low levels because there isn't a strong enough selection pressure against them to weed them out entirely.

 

At no point will a recessive gene switch to being a dominant one or vice versa just because it is selectively advantageous or disadvantageous. That will affect the rate at which the genes appear in the gene pool, but not whether they are dominant or recessive.

That's true but what makes a dominant gene to be weeded out?

There must be a system that makes it more likely for unnecessary alleles or genes to be deleted from the gene pool.

Genes can become dominant/recessive, dominance and recessiveness can change.

 

I just found how it's possible.

The way an allele becomes dominant over another allele is simple: a small RNA encoded by the first allele recognises a specific sequence on the second allele and blocks its expression.

It's a RNA-target mechanism.

"There are two possible models to explain how dominant and recessive relationships are controlled with the small RNA-target mechanism in a multi-allelic system. In Model 1, the dominant gene has several small RNAs that each act on a different allele (target). In Model 2, recessive genes have several targets, each recognised by a small RNA from the dominant gene."

http://www.inra.fr/en/Scientists-Students/Mechanisms-of-living-organisms/All-reports/Understanding-the-mechanism-behind-dominant-and-recessive-gene-expression/Chapter-Three-Back-to-evolution/(key)/2

 

Double recessive alleles which cause the fittest phenotype are not blocked because there is no dominant allele present and have many interactions with mRNA which imo causes RNA targets to become encoded RNA.

This process is controlled, otherwise all double recessive alleles which cause a livable phenotype would become dominant.

You have a very weird way to describe transcription and translation. Yet the main mechanism underlying cases that are not regulatory in nature are based on protein functions. Have you read and tried to understand String's and my earlier post?

The mRNA is just a transcript based on the DNA sequence and (again outside of regulation) the interaction is always the same, regardless of whether you got a recessive or dominant allele. The issue is that you are mixing up various levels of mechanisms (molecular, phenotype, selection) without seemingly having a clear view how the elements work or interact with each other.

I did read it but it does not explain what causes dominance or how it can change.

Your post gave an explanation on how alleles can behave dominant or recessive.

The mRNA is a transcript based on the DNA sequence but RNA still has to bind to the correct allele to form mRNA.

A dominant allele can block transcription of a recessive allele (this is a very important property) so there is something which causes RNA to bind to the correct alleles.

DNA is useless on its own, the interactions with RNA give DNA a purpose.

It's like our brain that can't survive without our body and vice versa.

However, OP seems to be confused about the definition of dominance as it does not have anything to do with RNA binding, nor does it have anything to do with fitness.

Dominance and recessiveness of alleles is only observable because of the interaction with RNA/ribosomes. RNA copies an allele and carries it to a ribosome where the allele is decoded into a protein which can cause a phenotype. The alleles which are copied (by RNA) and possible cause a phenotype are either dominant or recessive.(or something in between)

This process allows you to study the functionality of alleles and this process determines the functionality of alleles.

RNA is probably the only thing that interacts with DNA and decides what is dominant or recessive.

So if a recessive allele has to become dominant then imo only the interaction with RNA can cause this.

 

If you don't agree with this, then plz tell me why.

This idea is in my head for quite some time now and I can't find any real explanations on google.

Not sure why you would think this, there were dinosaurs in the polar regions..

The earth was warmer, polar regions were more habitable.

Antarctica was forested.

Alaska's flora resembled those growing in the temperate, subtropical and tropical regions of earth today.

Dinosaurs were probably mesotherm, they could not deal with the cold like mammmals.

http://www.livescience.com/46293-dinosaurs-had-in-between-blood.html