Epigenetics:)

[englishrick]

but,,,,,WHY DONT BLACK GUYS HAVE BLUE EYES?

i was under the impreshion that key eye color genes have mutated or changed to create the blue eye phenotype... These sorts of mutations are rare but it is where all the wonderful variety of people you see around you originally came from....imo

some scientists would assert that the whole concept of penetrance is a band-aid which exists to mask the reality that a fully understanding of the polygenic nature of a trait has not been achieved.

 

[Grat3fulh3ad]

but,,,,,WHY DONT BLACK GUYS HAVE BLUE EYES?

i was under the impreshion that key eye color genes have mutated or changed to create the blue eye phenotype... These sorts of mutations are rare but it is where all the wonderful variety of people you see around you originally came from....imo

Exactly, a genetic mutation. The blue eye phenotype is an example of a phenotype which is genetic NOT epigenetic. Thank you for offering further proof of the point i've been trying to get you to grasp. (BTW black guys can have blue eyes, all they need is the gene)

some scientists would assert that the whole concept of penetrance is a band-aid which exists to mask the reality that a fully understanding of the polygenic nature of a trait has not been achieved.

No one here is making any sort of claims to fully understand the workings of the epigenome. All I am doing is having to continually correct your assertion that traits are epigenetic, since they are traits for which we already have found a genetic cause.

Like blue eyes, or pale skin... Phenotypes which are 100% definitely for sure demonstrably genetic.

 

[GreenintheThumb]

Hay Green.....why do you sound like your commin round to the idea ,,?,,,check this out...

Are you serious? Is this level of stupidity POSSIBLE? You have got to be the dumbest mother fucker I've ever fucking MET! NEVER talk to me again. You are literally too stupid for anyone with HALF a brain to need to waste their time speaking to you. I've made so many posts in this thread trying to clean up the knowledge here and what you got out of all of this was that I was arguing AGAINST epigenetics!?!?! Stop reading anything remotely scientific you don't have the sense to make ANYTHING out of it. And stop quoting people and studies you don't understand. You're helping no one. Now go stay in the smoker's lounge where you belong. I encourage anyone who values their time to put this ignoramus on ignore. That's what I've come around to Rick.

Grat- How does environmental stimulus NOT change the chromatin? The example you gave of laying out in the sun: your skin is darkening because of changes in gene expression. Obviously your not mutating your genome but different genes are being turned on and off to elicit the darker skin. And those changes are passed through cell division, correct? I know you're kids aren't going to have your tan but aren't these cell memories passed on during cell division through epigenetic actions?

 

[W.P.]

I agree.

No one here is making any sort of claims to fully understand the workings of the epigenome. All I am doing is having to continually correct your assertion that traits are epigenetic, since they are traits for which we already have found a genetic cause.

Like blue eyes, or pale skin... Phenotypes which are 100% definitely for sure demonstrably genetic.
__________________

Just wonder IF and how to produce changes that are not genetically or stimuli produced ?


And just to clarify i understand the differences (i am not in that debate) , just wondering about possible technique or out side the box thinking on making or creating any epigenetic traits from my peers.

 

[Grat3fulh3ad]

Rick, it is funny the way you ask questions as though "the asking of a thing as though it proves something", actually proves something.

Is your understanding of the basic concepts of genetic inheritance really so poor that you do not know that there is a gene which is responsible for eye color?

The existence of the epigenome compliments our existing knowledge of genetic function.
In NO way does the existence of the epigenome negate what we already know about genetic inheritance. If you do not have a strong basic understanding of mendelian genetics, then you are going to continue to misunderstand everything you read about the epigenome.

I think this is a big part of your confusion... you think any of this makes mendelian genetic invalid or moot. Epigenetics adds to our current understanding it does not replace it.

 

[Grat3fulh3ad]

I agree. Just wonder IF and how to produce changes that are not genetically or stimuli produced ?


And just to clarify i understand the differences (i am not in that debate) , just wondering about possible technique or out side the box thinking on making or creating any epigenetic traits from my peers.

that's the whole point. one is going to do much better simply trying to provide their garden with what it needs to be its healthiest. no one knows what unexpressed traits cannabis might have, much less how to unlock them. what we do know, is that hybridization is still our best mechanism for unlocking epigenetic expression.

 

[Grat3fulh3ad]

Grat- How does environmental stimulus NOT change the chromatin? The example you gave of laying out in the sun: your skin is darkening because of changes in gene expression.

No changes are taking place at all.

Obviously your not mutating your genome but different genes are being turned on and off to elicit the darker skin. And those changes are passed through cell division, correct? I know you're kids aren't going to have your tan but aren't these cell memories passed on during cell division through epigenetic actions?

Well, you need an understanding of how skin works.
A tan is not caused by changes to any cell.
I am not manufacturing darkened skin cells, which divide into more darkened skin cells, because of a cell memory.
There are already melanocytes in your skin, and their job is to produce melanin (the pigment which makes skin dark) which they do all the time, and in response to sunlight, increased exposure to the sun only makes them do it faster.
It is a job that cell is already doing under normal circumstances.

Getting tan is your body adapting to increased sunlight without mutation or chromosomal change. It is just a type of cell doing what it is designed to do.

Lots of phenotypical differences are simply some specialized cell kicking in when circumstances are right.

 

[Grat3fulh3ad]

Tanning is the result of structural mechanisms which are in place as a result of genotype.

"The appearance of the skin is partly due to the reddish pigment in the blood of the superficial vessels. In the main, however, it is determined by melanin, a pigment manufactured by dendritic cells called melanocytes, found among the basal cells of the epidermis. Their numbers in any one region of the body, which range from about 1,000 to more than 2,000 per square millimetre, are roughly the same within and between races; the blondest whites have as many as the darkest blacks. Colour differences are due solely to the amount of melanin produced and the nature of the pigment granules. When the skin becomes tanned on exposure to sunlight, the melanocytes do not increase in number, only in activity." ("Integumentary Systems, Pigmentation", Britannica CD. Version 97. Encyclopaedia Britannica, Inc., 1997.)

When you get a tan, what is actually happening is that the melanocytes are producing melanin pigment in reaction to ultraviolet light in sunlight. Ultraviolet light stimulates melanin production. The pigment has the effect of absorbing the UV radiation in sunlight, so it protects the cells from UV damage. Melanin production takes a fair amount of time -- that is why most people cannot get a tan in one day. You have to expose yourself to UV light for a short period of time to activate the melanocytes. They produce melanin over the course of hours. By repeating this process over 5 to 7 days pigment builds up in your cells to a level that is protective.

The previous paragraph applies to Caucasians. In a variety of other races, melanin production is continuous, so the skin is always pigmented to some degree. In these races the incidence of skin cancer is much lower because cells are constantly protected from UV radiation by melanin.

The difference in caucasians and these other races is in their genome, the phenotypes 'always on' and 'UV activated' are genetic. In fact it is a good example of a trait which is determined by multiple genetic loci.
In addition to the action of UV light directly increasing pigment production,

Melanocyte-stimulating hormone (MSH) is produced by the pituitary gland. MSH flows through the bloodstream and reaches the melanocytes, encouraging them to produce more melanin (for example, a person injected with a large dose of MSH will get darker). The pituitary gland is actually quite interesting -- it is tied into the optic nerve, which means that it can sense light.

so there are multiple mechanisms by which people tan, to adapt, without chromosomal change or mutation.

 

[W.P.]

much less how to unlock them

Thanks for the reply. That was a key i had hoped you held.

Oh well no snake oil for me

 

[GreenintheThumb]

Grat- How does the cell physically 'turn on' melanin production...some genes have to be turned on, right? And how are those genes turned on? Could it be through epigenetic action? Isn't any change in gene expression due to environment an epigenetic effect?

 

[Grat3fulh3ad]

Grat- How does the cell physically 'turn on' melanin production...some genes have to be turned on, right? And how are those genes turned on? Could it be through epigenetic action? Isn't any change in gene expression due to environment an epigenetic effect?

it is not a trait of the cell that gets 'turned on'. There are many stimuli which induce melanin production. It is simply a cell doing what it is designed to do.

melanocytes produce melanin pigment.

myocyte contract, relax, and generate electrical impulses.

neurons convert electrical impulses to chemical signals and back again.

a leukocyte is capable of motility, and defends the body against infection and disease by ingesting foreign materials and cellular debris, by destroying infectious agents and cancer cells, or by producing antibodies.

Unless you are saying that every single cellular process is a heritable chromosomal change ... but that sounds too "rick-esque" to be what you mean...

 

[Grat3fulh3ad]

Been thinking about my closing remarks on the subject...

If it is as you assert, greenthumbs, and everything we already knew about the way DNA and RNA use chemical signals to direct the functions of a cell, is now called epigenetics...

then epigenetics is of almost no significance to almost everyone, and the only lesson anyone need take from this thread is:
Grow healthy plants and take healthy cuttings.


If, on the other hand... the epigenome is more than and separate from those previously observed biochemical processes, and is a conditionally permanent state, then there is potential to unlock something really cool...

 

[GreenintheThumb]

the only lesson anyone need take from this thread is:
Grow healthy plants and take healthy cuttings..

Yeah, I think regardless of how we look at it, that is the message to take on the subject of cannabis.

But I think you're right, I was conceptualizing everything as being involved with gene expression and it's not. I think you're right on the tan example. Now if prolonged sun exposure caused the activation of genes that resulted in cells growing more melanocytes and this was heritable it'd be epigenetic.

 

[englishrick]

ok green,,,no prob

 

[Grat3fulh3ad]

Yeah, I think regardless of how we look at it, that is the message to take on the subject of cannabis.

But I think you're right, I was conceptualizing everything as being involved with gene expression and it's not. I think you're right on the tan example. Now if prolonged sun exposure caused the activation of genes that resulted in cells growing more melanocytes and this was heritable it'd be epigenetic.

agreed

 

[kopite]

Grat3fulh3ad,

Would you say that histones are key in epigenetics?, also with regards to a plants memory ie as in triggering flower 12/12 is this epigentics at work or an in built genetic memory?

Kopite

 

[Grat3fulh3ad]

Histones are a large part of epigenetic change, yes... key, but not 'the key'

The mechanism by which phototropic plants switch from vegetative growth, I would classify as a genetic trait, or a plant system functioning according to its design... It works like this... When sunlight is hitting the plant, The plant is producing certain hormones(phytochromes I think)... these hormones inhibit the production of florigen, the flowering hormone... When the production of the inhibiting hormones falls below a certian level, then the flowering hormone builds up to a level which triggers flower production... I would guess in autoflowering plants a genetic difference allows for continuous florigen production...