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Genetic Drift


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So the feminized seed thread is a great discussion that led to GM's comment regarding his method "Clone from clone until genetic drift then work from seed" sorry if that is paraphrased poorly. Please set me straight to how you would present the concept.

 

Question is - what have the experienced (or inexperienced) growers witnessed first hand as it relates to genetic drift from clones of clones cloned from clones of clones that were cloned from a clone that was a clone? I know of people who ran one clone for years and if it drifted it was in a good way because it definitely was as good if not better at the end. All from one seed mistakenly left in a bag of transferred product.

 

Some information on the subject for those unfamiliar or as a source of reference.

 

http://www.apsnet.org/edcenter/advanced/topics/PopGenetics/Pages/geneticdrift.aspx

 
Population Genetics of Plant Pathogens
Genetic Drift

It should now be clear that population size will affect the number of alleles present in a population. But small population sizes also introduce a random element called genetic drift into the population genetics of organisms.

Genetic drift is a process in which allele frequencies within a population change by chance alone as a result of sampling error from generation to generation. Genetic drift is a random process that can lead to large changes in populations over a short period of time. Random drift is caused by recurring small population sizes, severe reductions in population size called "bottlenecks" and founder events where a new population starts from a small number of individuals. Genetic drift leads to fixation of alleles or genotypes in populations. Drift increases the inbreeding coefficient and increases homozygosity as a result of removing alleles. Drift is probably common in populations that undergo regular cycles of extinction and recolonization. This may be especially important in natural ecosystems where both plants and pathogens are likely to have a patchy distribution where each patch is a small population.

Because allele frequencies do not change in any predetermined direction in this process, we also call genetic drift "random drift" or "random genetic drift." The sampling error can occur in at least three ways. We will consider these in the context of pathogen populations in plant pathosystems:

  • Small recurring population size occurs when there are not many host plants in the area to infect, or when the environment is not optimal for infection.
  •  A genetic bottleneck, or severe reduction in population size, occurs when the plant population is removed (e.g. harvest of the crop), or when the environment changes to prevent infection of the plant or to kill the pathogen directly (e.g. periods of hot, dry weather or a deep freeze).
  • A founder effect occurs when a small number of individuals, representing only a small fraction of the total genetic variation in a species, starts a new population. A founder event occurs when one or two infected plants slip through a quarantine and introduce a disease into an area where the disease did not previously exist.
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I have always felt people in the marijuana arena misinterpret 'genetic drift'.  This is caused by successive generations.  A clone is still the original.

 

 Loss of vigor, growth, potency etc., which many consider 'drift', is simply a matter of genetics and environment basically.

 

 I have had strains that pooted out at about 7 years(original WW) and strains that have lasted 25+ years(BG) with the most minimal of changes.

 

 So, we see 'drift' daily in the marijuana seed market via land strains and many other items.  Genetics and environment account for most of what people in the marijuana community consider 'drift". IMO of course.

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I have always felt people in the marijuana arena misinterpret 'genetic drift'.  This is caused by successive generations.  A clone is still the original.

 

 Loss of vigor, growth, potency etc., which many consider 'drift', is simply a matter of genetics and environment basically.

 

 I have had strains that pooted out at about 7 years(original WW) and strains that have lasted 25+ years(BG) with the most minimal of changes.

 

 So, we see 'drift' daily in the marijuana seed market via land strains and many other items.  Genetics and environment account for most of what people in the marijuana community consider 'drift". IMO of course.

 

That would be my estimation but regardless of my knowledge of a subject I'm not in the business of telling someone else what they observed when I wasn't there (or even if I was). I wonder if a low-potency crop is attributed to drift when it was environment. But would clones of that weaker potency crop yield a weaker potency strain from then on or would its inherent genetics allow for a full recovery of potential once environment was corrected?

 

How do you mean "pooted out", please? What were the signs or symptoms that you noted that it had gone off the rails?

 

It is a fascinating concept to me and thanks for your input.

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That would be my estimation but regardless of my knowledge of a subject I'm not in the business of telling someone else what they observed when I wasn't there (or even if I was). I wonder if a low-potency crop is attributed to drift when it was environment. But would clones of that weaker potency crop yield a weaker potency strain from then on or would its inherent genetics allow for a full recovery of potential once environment was corrected?

 

It can absolutely recover. It is still the same plant. You can take 6 clones, give them to 6 growers, and all 6 final products will range and differ due to environmental factors.  When a plant 'may' not recover is when it was actually attacked by a virus in some cases.  It can actually alter nuclei thus causing a DNA alteration.  But otherwise, it is still the same plant.

 

 

 

 

How do you mean "pooted out", please? What were the signs or symptoms that you noted that it had gone off the rails?

 

It is a fascinating concept to me and thanks for your input.

 

 Well, a marijuana plant , "technically", is not meant to grow for 25+ years.  So this is a trait that may not necessarily exist in all strains.  Not many people take the time to grow a single plant for 25+ years to find out. They make crosses or do inbreeding(which can cause drift) to produce seeds to maintain their line.  With the WW line, it appears to only really like to live for 5-10 years. I have corroborated this with other growers as well.  It isnothing wrong with that, just that it loses vigor, potency etc at around that time.  That is just a genetic marker issue.  And, makes one want to then keep a good seed stock with good variety because you will need to run seed crops every so many years and you must be wary of inbreeding issues when doing so. This is where drift, mutation and bottlenecking come into play.

 

I am just using those two examples because they are very clear representatives.

 

 If I can find people with males still full of vigor after 25 years or so, I would love to do a cross with them for BG.  It would obviously encourage that genetic trait. 

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this is correct. drift isn't necessarily from a clone of a clone.

with that said....unless cloning is performed under sterile conditions fungus ultimately will find its way to introduce pathogens into the dna stream.  sometimes this causes great mutations other times nasty ones. some can be "corrected" sometimes with just successive cloning. After I repaired my sexually confused Tahoe OG, then sterile cultured it, married it with my cherished cultured Medicine Man.......I haven't refreshed the stock since. that was in 2010. I see no issues at this time, and clone its clones monthly. My issue is that I've cloned several, from several, and there are subtle differences between them. I should number them , keep the best cull the rest,,.....then just take clones from one host. but I'm lazy and deciding which is the best is difficult. Nobody I know can detect the differences in the finished product, but most of us would see it in growth.

 

bacteria and fungus is used to facilitate a drift in genetics, incorrectly called a genetic drift by most of us. the bacteria and fungus is among us always. my dirty scalpels and stained cutting board goes a long way in making changes. I don't care though, because refreshing stock with new cultured stock is very exciting for me.

Most "drift" seen is exactly as described in the thread. one plant did well, another was over fed, another clone  took a long time to develop healthy leaf structure, on and on...... so we use "genetic drift" card as the excuse to redeem our dirty cloning jobs.....

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I have always felt people in the marijuana arena misinterpret 'genetic drift'.  This is caused by successive generations.  A clone is still the original.

 

Spot on!  It is a common misused phrase in the community.  The concept of genetic drift requires pollination and offspring.  Clones are not offspring.  When people talk about cloning from a clone from a clone, they are referring to "passage".  Eventually, after too many passages, a cell line will 'wear out'. I think this is what people are calling 'genetic drift'.   Here is a quick excerpt from wiki will explain:

 

In biology, a subculture is a new cell or microbiological culture made by transferring some or all cells from a previous culture to fresh growth medium. This action is called subculturing or passaging the cells. Subculture is used to prolong the life and/or expand the number of cells or microorganisms in the culture.

 

Passage number

It is often important to record the approximate number of divisions cells have had in culture by recording the number of passages or subcultures. In the case of plant tissue cells somaclonal variation may arise over long periods in culture. -wiki

 

passage number aka what stoners call genetic drift.

Edited by garyfisher
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Spot on!  It is a common misused phrase in the community.  The concept of genetic drift requires pollination and offspring.  Clones are not offspring.  When people talk about cloning from a clone from a clone, they are referring to "passage".  Eventually, after too many passages, a cell line will 'wear out'. I think this is what people are calling 'genetic drift'.   Here is a quick excerpt from wiki will explain:

 

In biology, a subculture is a new cell or microbiological culture made by transferring some or all cells from a previous culture to fresh growth medium. This action is called subculturing or passaging the cells. Subculture is used to prolong the life and/or expand the number of cells or microorganisms in the culture.

 

Passage number

It is often important to record the approximate number of divisions cells have had in culture by recording the number of passages or subcultures. In the case of plant tissue cells somaclonal variation may arise over long periods in culture. -wiki

 

passage number aka what stoners call genetic drift.

 

Interesting that the somaclonal variation doesn't have a link in the reference since that seems to be the issue RE: "cell line wear out" which is what I suppose the "stoners" are trying to understand and articulate.

 

http://en.wikipedia.org/wiki/Somaclonal_variation

 

Somaclonal variation is the variation seen in plants that have been produced by plant tissue culture. Chromosomal rearrangements are an important source of this variation.

The term somaclonal variation is a phenomenon of broad taxonomic occurrence, reported for species of different ploidy levels, and for outcrossing and inbreeding, vegetatively and seed propagated, and cultivated and non-cultivated plants. Characters affected include both qualitative and quantitative traits.

 

Somaclonal variation is not restricted to, but is particularly common in, plants regenerated from callus. The variations can be genotypic or phenotypic, which in the latter case can be either genetic or epigenetic in origin. Typical genetic alterations are: changes in chromosome numbers (polyploidy and aneuploidy), chromosome structure (translocations, deletions, insertions and duplications) and DNA sequence (base mutations). A typical epigenetics-related event would be gene methylation.

 

If no visual, morphogenic changes are apparent, other plant screening procedures must be applied. There are both benefits and disadvantages to somaclonal variation. The phenomenon of high variability in individuals from plant cell cultures or adventitious shoots has been named somaclonal variation.

 

Awesome. Thanks for the replies.

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be interesting to read of bacteria and fungus that actually change dna. i thought that was something that only happened in the 50s films about giant plants eating people ya know? :P

 

This is what I was thinking about. Will DNA adapt to environment without pollination and the normal process of adaptation? If a region experienced a temperature increase it would be logical that annuals would account for this genetically and next year's seeds would be programmed to combat the change.

 

How long did it take for Afghan Kush to get so sticky?

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be interesting to read of bacteria and fungus that actually change dna. i thought that was something that only happened in the 50s films about giant plants eating people ya know? :P

agrobacterium. that will get you started. Its a vector found in crown gall disease of trees, and illegal to purchase without permits. Easily carries all kinds of protins/genes, like the GFP, gold,virus;, etc, and change dna forever. sometimes ridiculously large plants, sometimes with only 1 blade leafs, sometimes they glow in the dark.

tpain can read more in my tissue cultured mj thread. I have photos if interested.

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This is what I was thinking about. Will DNA adapt to environment without pollination and the normal process of adaptation? If a region experienced a temperature increase it would be logical that annuals would account for this genetically and next year's seeds would be programmed to combat the change.

 

How long did it take for Afghan Kush to get so sticky?

absolutely affirmative.

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I would like to add that in my own personal experience with three strains that have been around for a over 20 years; Chem D, OG Kush, Original Diesel aka headband, I haven't seen any changes in their traits for the 6 years I have been graced with their presence. I have heard about growers using excuses like genetic drift when all it is are growing issues they have not solved and are desperate to find the answer. On the other hand, perfectly stable great strains are very difficult to attain because they are held like the holy grail. 

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thank you, I was awaiting the keen observation

I used this language because most here recognize what I intend.

In fact, cloning can and does change dna record unless performed in sterile conditions.

I can dirty clone and forever screw up a cultivar, sometimes often on purpose. I never stated that "all" of my genetics "drift", much to the opposite actually stated in above post. it can happen on the first cut, or never. I try to be clean, but I'm lazy sometimes and just don't care . No aspirations here of providing top genetics to anyone but my patients, and none of seed making either. If so, all of my clones would be treated exactly as my cultures are, sterilized plant material, equipment, and media. Its really not an issue at all for the average grower/patient. sometimes small differences are noticed by me and I blow them off, until I cannot any longer, then I refresh stock with cultures, and that's when I see clearly the follies of my dirty cloning.

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thank you, I was awaiting the keen observation

I used this language because most here recognize what I intend.

In fact, cloning can and does change dna record unless performed in sterile conditions.

I can dirty clone and forever screw up a cultivar, sometimes often on purpose. I never stated that "all" of my genetics "drift", much to the opposite actually stated in above post. it can happen on the first cut, or never. I try to be clean, but I'm lazy sometimes and just don't care . No aspirations here of providing top genetics to anyone but my patients, and none of seed making either. If so, all of my clones would be treated exactly as my cultures are, sterilized plant material, equipment, and media. Its really not an issue at all for the average grower/patient. sometimes small differences are noticed by me and I blow them off, until I cannot any longer, then I refresh stock with cultures, and that's when I see clearly the follies of my dirty cloning.

Cloning doesn't change DNA. You are mistaken and something else is responsible for the changes you are seeing. 

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you are being foolish resto. I assure you I create freaks, freaks that continue on their freakhood, because their dna is forever changed. A common cold, many bacterium, even insects cause genetic changes in the human and plant genome cause dna changes often when cloning, some purposeful and detectable. I just have very little control on the outcome is all. I have pics of freaks I've shown here, sorry you missed them.

 

if you care enough to argue you'd be more successful spouting off about that which you may know of.

Edited by grassmatch
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you are being foolish resto. I assure you I create freaks, freaks that continue on their freakhood, because their dna is forever changed. A common cold, many bacterium, even insects cause genetic changes in the human and plant genome cause dna changes often when cloning, some purposeful and detectable. I just have very little control on the outcome is all. I have pics of freaks I've shown here, sorry you missed them.

 

if you care enough to argue you'd be more successful spouting off about that which you may know of.

I've seen all your pics. None have shown definite DNA change from cloning. Why did you even bring that up when you know those pics have no value to bolster your position of weakness in this topic? You are grasping at straws to confirm you are right. Might as well do your usual cut and paste of everything on the net that proves you right while you continue to be wrong. 

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Cloning doesn't change DNA. You are mistaken and something else is responsible for the changes you are seeing. 

First of all, You're not "cloning" dna.

 

Second of all, grassmatch was referring to Somaclonal variation  when he stated genetic drift.  

Thirdly, Yes DNA changes, apparently you missed the posts at the top of this thread by me and YESMICHIGAN.

Chromosomal rearrangements are an important source of this variation.

 

What do you think chromosomal rearrangements are?  DER DER

:rolleyes:

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Ive had a cut of DJ Shorts clone only Blueberry that Ive had since 2010 theres no degradation in quality that I have noticed same thing with Docs Bubba OG I was gifted one fem bean and since Ive grown well over 50 mature harvested plants via cloning from that one lone bean.

Were these successive cloning events or clones from a single or couple mother(s)? 

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All I can say is my genetics are the same after decades of cloning. None of us have a DNA checker so you can't prove you are right, you are guessing.  So all we can do is look at our strains and see if they change. Mine didn't, so the way I clone doesn't change my strains. Anyone can F up, it takes determination to sustain a grow or a strain, with no excuses like cloning F ed up my grow.

 

Go ahead and report your cloning genetics failures for evidence.

 

What I do know is that you can clone like a wild dog for as long as you like and things can work out wonderfully for you and your strains. 

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