Basic genetics explained

[Only Ornamental]

Hi GitT

Thanks for taking the time to take a look at that.

Yeah I see that the body of the paper shows that there are 9 pairs of autosomes that are very similar, the X looks like the autosomes but if measured carefully can be distinguished from them as it is slightly larger, and that the Y basically sticks out like a sore thumb with its heterochromatic arm and yet larger size than the X. It is just that in the abstract and in the body of the paper at least once, they flatly state that the X is the largest.

I remember the reference to the 1943 paper (had something to do with visible light microscopy techniques, no?), do you really think that explains it? I haven't had time to read it again, but I don't think that is the case. I'll keep your comment in mind when I re-read it. Thanks.

By the way, I would be interested to know more about your work with synthetic seeds.

Well, the legend of Fig. 4 also has an error

5S rDNA: green signals

'yellow' would be correct, and I found (wasn't reading all and wasn't specifically looking for it) also a flaw regarding the use of abbreviations. My general impression of that paper is rather moderate...
PLOS One isn't a bad journal, maybe it's because the authors are from Russia. No, I'm no racist! I simply suspect they hired someone to translate and didn't recheck .

 

[mofeta]

Wouldn't hemp that is required to be grown from seed every year be a more complicated organism? Not to mention actual breeding involved to create populations with traits that we may not want with medical cannabis?

This is correct in my view:

I was also wondering why the distinction between medicinal cannabis and fibre hemp.

Maybe Tom means that hemp breeding 'only' focusses on a few traits like size, fibre quantity and quality, low branching (strong apical dominance), disease resistance, and a certain flowering onset and crop maturity as major ones. Size, fibre content and quality, and health show a high correlation with hybrid vigour, low branching is and has always (?) been part of industrial/agricultural hemp and flowering time isn't that much of a trouble; hence hemp require neither special breeding skills nor too much luck .

Since it has become clear that the psychoactivity of cannabis is a massively multivariate quality, the result of many (maybe even triple digits) compounds interacting with out bodies in very complicated ways, it is different in important ways. The very small, numerous difference in genome that separate dank from bunk require more focused efforts than those required for hemp breeding. The constellation of traits and their associated alleles that makes for an "excellent" hemp plant is much less complicated than the large number of alleles, interacting in more complicated non-mendelian ways, that make up an "excellent" drug variety.

I always wondered why there's such a difference between nowadays crop breeding and cannabis breeding... Many techniques and approaches used in the canna world are an old hat in agriculture and have been used when... 100 years ago?

There is no difference. All the problems and ideas people discuss on the various cannabis forums have been solved or thought of already for, well not 100 yrs, but a long time. All one has to do is pick up a textbook an do a little reading.

 

[mofeta]

Do you see many in the so called cannabis community doing the likes of dunnetts testing? I don't.

Hi Yard dog
Welcome to ICMag

If you literally mean how many weed breeders am I aware of that use statistical tools in their breeding program, I would say I could count them on two hands.

hmmm hopeful monsters or hopeless ? I'd of thought the easiest way would be to take the elites and do wide crosses on them? the main stumbling block to that is actually knowing what ancestors that line has. But since most drug pool cannabis is closely related I can see the point in crossing the known closely related lines and going from there. But like you've pointed out it takes numbers and a bit of work, that is surely too much for most!.

Yeah I am of the camp that I don't really consider any drug cultivars different enough to apply the term 'wide' (in the strict sense anyway) to a mating between them.

I am also tired of people being so obsessed with the ancestry of a specific starting propagule. All you need to know about the individual will reveal itself to the breeder with a proper knowledge of the techniques used to suss out genotype. I think this obsessiion with past lineage was sparked (like many memes in our little world of weed) by a few lines in Rob Clarke's first book.

it's known that transgressive segregation will occur more in crossed selfed lines, and thus the closer the parental starting lines the better especially if you are to start looking in the F2's.

That is a more complicated topic that I will save for the "Tom Hill's Breeding Philosophy" thread I'm going to start (hopefully this evening).

 

[Sam_Skunkman]

I have bred both industrial and medical as well as recreational. I started with recreational, then became interested in medical and industrial. While the three certainly have differences in their end goals, I find that Cannabis is Cannabis. Recreational is focused on plant traits like early maturation, cannabinoid content or lack of any besides THC, as well as the terpenes that contribute to the taste, smell, and effects, traits like vigor, branching, pest and disease resistance, leaf to flower ratios, resin characterisitics, as well as all female, autoflowering, and more I can't think of at the moment.
Medical requires many of the above with a special focus on chemotypes for the cannabinoids and or terpenes or other targets like GLA's.
Industrial requires seed yields, seed size may be important, fiber content, fiber type, hurd content, celulose type, biomass content, cannabinoid content, like low THC, maturation time, tropical and equatorial low THC varieties, as well as pest and disease resistance, tolerance to drought, sexual expression like monoecious, unisexual, even cannabinoids like CBD recently. As the expression of quantitative agronomic traits depend more or less strongly on the environment as well as different locations will ne requiring different traits. The newest work using genome minning or "tilling" like increasing the Olecic acid content over GLA for improved resistance to rancidity and heat.
I did not add using GM to add resistance to botrytris or other diseases or pests. But I guess sooner or later it will be done and made available.

-SamS

 

[harry74]

me coming from the rocks

me coming from the rocks

If you mean Neanderthal... you'd be either disappointed or not astounded at all: Although not our direct ancestors, they have/had only 0.12% genetic difference compared to modern humans (I picked that from Wiki). Guess you could be right with your statement .

Paleogenetic investigations by the Complutense University of Madrid[6] indicate that the Basque people have a genetic profile coincident with the rest of the European population and that goes back to Prehistoric times.[7] The haplotype of the mitochondrial DNA known as U5 entered in Europe during the Upper Paleolithic[8] and developed varieties as the U8a, native of the Basque Country, which is considered to be Prehistoric,[9] and as the J group, which is also frequent in the Basque population.[9]

The haplogroup R1b, which originated during the last ice age at least 18,500 years ago,[16] when Human groups settled in the south of Europe and that is currently common in the European population, can be found most frequently in the Basque Country (91%), Wales (89%) and Ireland (81%). The current population of the R1b from western Europe would probably come from a climatic refuge in the Iberian Peninsula, where the haplogroup R1b1c (R1b1b2 or R1b3) originated. During the Allerød oscillation, circa 12,000 years ago, descendants of this population would have repopulated Western Europe.[12] The rare variety R1b1c4 (R1b1b2a2c) has almost always been found among the Basque people, both in the Northern and Southern Basque Country. The variety R1b1c6 (R1b1b2a2d) registers a high incidence in the Basque population, 19%.[17]

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

https://www.youtube.com/watch?v=zRhDnV-NpT0

Coming in from the rock - Prince Far I

 

[harry74]

My old home

My old home



I used to stay there for the summer.....

in the good old times

Bloody civilized people, bloody romans.....

Well, they brought us wine to be honest

 

[harry74]

I have bred both industrial and medical as well as recreational. I started with recreational, then became interested in medical and industrial. While the three certainly have differences in their end goals, I find that Cannabis is Cannabis. Recreational is focused on plant traits like early maturation, cannabinoid content or lack of any besides THC, as well as the terpenes that contribute to the taste, smell, and effects, traits like vigor, branching, pest and disease resistance, leaf to flower ratios, resin characterisitics, as well as all female, autoflowering, and more I can't think of at the moment.
Medical requires many of the above with a special focus on chemotypes for the cannabinoids and or terpenes or other targets like GLA's.
Industrial requires seed yields, seed size may be important, fiber content, fiber type, hurd content, celulose type, biomass content, cannabinoid content, like low THC, maturation time, tropical and equatorial low THC varieties, as well as pest and disease resistance, tolerance to drought, sexual expression like monoecious, unisexual, even cannabinoids like CBD recently. As the expression of quantitative agronomic traits depend more or less strongly on the environment as well as different locations will ne requiring different traits. The newest work using genome minning or "tilling" like increasing the Olecic acid content over GLA for improved resistance to rancidity and heat.
I did not add using GM to add resistance to botrytris or other diseases or pests. But I guess sooner or later it will be done and made available.

-SamS

Terpenes don´t contribute to the effect IMO.


The idea of breeding towards just THC forgetting the rest of cannabinoids is nosense IMO.

You are going nowhere IMO....

Nothing personal

 

[LyryC]

Looks like school didn't end

Looks like school didn't end

I have so much to learn! This is great - more please! Thank you!



Lots of commendable legends in here

I don't strive to be a breeder but I hope to learn more about what we all love in hopes to be able to better serve myself and others with this information or atleast the source of it so that the community as a whole can come to a consensus and understanding of this foggy subject.

I feel very blessed and spoiled being able to be able to learn from ya'll

 

[Sam_Skunkman]

Terpenes don´t contribute to the effect IMO.

I beg to differ.

The idea of breeding towards just THC forgetting the rest of cannabinoids is nosense IMO.

If you are after better recreational Cannabis what other Cannabinoid besides THC should you be breeding for? Please list it. If your focus is something besides the recreational high then it is not about effects.

You are going nowhere IMO....

Nothing personal

I am not upset by what you say at all. I do know that your are wrong about your opinion, so be it.
-SamS

 

[Yard dog]

Hi Yard dog
Welcome to ICMag

If you literally mean how many weed breeders am I aware of that use statistical tools in their breeding program, I would say I could count them on two hands.



Yeah I am of the camp that I don't really consider any drug cultivars different enough to apply the term 'wide' (in the strict sense anyway) to a mating between them.

I am also tired of people being so obsessed with the ancestry of a specific starting propagule. All you need to know about the individual will reveal itself to the breeder with a proper knowledge of the techniques used to suss out genotype. I think this obsessiion with past lineage was sparked (like many memes in our little world of weed) by a few lines in Rob Clarke's first book.





That is a more complicated topic that I will save for the "Tom Hill's Breeding Philosophy" thread I'm going to start (hopefully this evening).

Firstly, thanks for the welcome (though we have certainly met before).

Well to have the number need two hands is more than I actually imagined, I used to be obsessed with the ancestry of lines, when I started doing my own work with lines I started to realize that it doesn't really matter on the starting point but more where the lines went, though I did notice if one was to use a so called elite in a mating it more often than not was a better starting point! though now I have lines to go looking for standouts, it is very time consuming and in need of higher numbers but such is life!

I look forward to the new thread

 

[ozza]

Terpenes don´t contribute to the effect IMO.


The idea of breeding towards just THC forgetting the rest of cannabinoids is nosense IMO.

You are going nowhere IMO....

Nothing personal

Terpenes do contribute IMO

 

[harry74]

I am not upset by what you say at all. I do know that your are wrong about your opinion, so be it.
-SamS

Well, there is a thread called TGA concerning potency; I have grown nothing from TGA, but growers were talking about nice smell and tasty weed but somehow lacking potency, if what you mean is that improves potency somehow.....

For the rest of the day, I´m not going to explain again " The Chef Pastry Theory" and the real true is that I´ve got nothing solid to prove it. You are supposed to have more solid,data,info than me.......
What I can do ? I have to gather somenthing that is solid.....
I´ll try the upcoming months and If I´m able to get some silver bullets for my Magnum, we will have a nice shoot out....

So you can get ready your tools Cowboy...

 

[ozza]

Well, there is a thread called TGA concerning potency; I have grown nothing from TGA, but growers were talking about nice smell and tasty weed but somehow lacking potency, if what you mean is that improves potency somehow.....

For the rest of the day, I´m not going to explain again " The Chef Pastry Theory" and the real true is that I´ve got nothing solid to prove it. You are supposed to have more solid,data,info than me.......
What I can do ? I have to gather somenthing that is solid.....
I´ll try the upcoming months and If I´m able to get some silver bullets for my Magnum, we will have a nice shoot out....

So you can get ready your tools Cowboy...

butting in again

I think terpenes have agreat deal to do with highs, because of my experience with other plants namely herbs. Many of these herbs have terpenes similiar to canabis and are used for the medical and recreational benefits.

I think all these things combined contribute to the high or stone.

 

[harry74]

Pure Aries, Like a Battering Ram...lol

Don´t worry.

I don´t need any key

I´ll break in

 

[Yard dog]

Terpenes don´t contribute to the effect IMO.


The idea of breeding towards just THC forgetting the rest of cannabinoids is nosense IMO.

You are going nowhere IMO....

Nothing personal

Yet people still want the RKS! well why? it can't just be for that stink can it? or would people want the "cheese" without the stink or the fuel of "ECSD" ?.

now if you accept that most drug pool cannabis is linked and have been bred for THC (esp indoor under lights) and certainly round me and in the UK/Europe that has been what has been done, then often the stand outs are those with different or certain stinks to their profile!

Now if it is bullshit then it works!! as those stinky buds certainly shift faster than the others! There's also things like certain smells affiliated to buds often indicate how long that bud will stay ripe or oxidise faster than others, there's certainly a terpene that effects me as it seems to trigger hayfever like effects (I've often seen it linked to myrcene, though I tend to go towards pinene.

 

[GreenintheThumb]

Was it having opinions on things you know nothing about that made you the King of Cardboard harry?

Yard Dog: People always want what they cannot have. If everyone loved RKS so much why are there no cuts of it still around? Because as a community it wasn't deemed worthy of keeping. You doubt that people want RKS because of the stink? Exactly what trait do you think the line had in it that people do want? I've noticed that most of the people who do want it never had it to begin with so they're really basing it on stories. And the only stories I see about it are that it reeked. Roll through some Chem hybrids and you can get some stinky burning tires sprayed with skunk smells along with effects that people want these days.

 

[KiefSweat]

or it could have been basic genetics, you lose the parents you can't make f1 stock anymore.

 

[GreenintheThumb]

You know what's simpler than basic genetics for cannabis? Asexual propagation. Too bad no one kept a cut around. I guess the community will have to just keep bugging Sam about it.

 

[GreenintheThumb]

Back crossing is exactly what I would start with, 6x back will get your seed stock over 90% similar to the original cut.

So the OP made this comment in a different thread and I figured it was worth noting that this notion is plainly false. It's a mistake many breeders make and is an oversimplification of the mathematics of inheritance.

Chimera made some comments about this subject and I'll leave them here.

Cubing...a myth.
"you’ve just discovered the biggest myth (IMNSHO) of marijuana breeding- it is a mistake that almost EVERYONE makes (including many of the most respected breeders!).

Backcrossing will not stabilize a strain at all- it is a technique that SHOULD be used to reinforce or stabilize a particular trait, but not all of them.

For e.g.- G13 is a clone, which I would bet my life on is not true breeding for every, or even most traits- this means that it is heterozygous for these traits- it has two alleles (different versions of a gene). No matter how many times you backcross to it, it will always donate either of the two alleles to the offspring. This problem can be compounded by the fact that the original male used in the cross (in this case hashplant) may have donated a third allele to the pool- kinda makes things even more difficult!

So what does backcrossing do?
It creates a population that has a great deal of the same genes as the mother clone. From this population, if enough plants are grown, individuals can be chosen that have all the same traits as the mother, for use in creating offspring that are similar (the same maybe) as the original clone.
Another problem that can arise is this- there are three possibilities for the expression of a monogenic (controlled by one gene pair) trait.

We have dominant, recessive, and co-dominant conditions.

In the dominant condition, genotypically AA or Aa, the plants of these genotypes will look the same (will have the same phenotype, for that trait).

Recessive- aa will have a phenotype

Co-dominant- Aa- these plants will look different from the AA and the aa.

A perfect example of this is the AB blood types in humans:

Type A blood is either AA or AO
Type B blood is either BB or BO
Type AB blood is ONLY AB
Type O blood is OO.

In this case there are three alleles (notated A, B, and O respectively).

If the clone has a trait controlled by a co-dominant relationship- i.e. the clone is Aa (AB in the blood example) we will never have ALL plants showing the trait- here is why:

Suppose the clone mother is Aa- the simplest possibility is that the dad used contributes one of his alleles,
let us say A. That mean the boy being use for the first backcross is either AA or Aa. We therefore have two possibilities:

1) If he is AA- we have AA X Aa- 50% of the offspring are AA, 50% are Aa. (you can do the punnett square to prove this to yourself).

In this case only 50% of the offspring show the desired phenotype (Aa genotype)!

2) If the boy being used is Aa- we have Aa X Aa (again do the punnett square) this gives a typical F2 type segregation- 25% AA, 50% Aa, and 25% aa.
This shows that a co-dominant trait can ONLY have 50% of the offspring showing the desired trait (Aa genotype) in a backcross.

If the phenotype is controlled by a dominant condition- see example #1- all 100% show the desired phenotype, but only 50% will breed true for it.

If the phenotype is controlled by a recessive condition- see example #2- only 25% will show the desired phenotype, however if used for breeding these will all breed true if mated to another aa individual.

Now- if the original dad (hashplant) donates an 'a' allele, we only have the possibilities that the offspring, from which the backcross boy will be chosen, will be either Aa or aa.
For the Aa boy, see #2.
For the aa boy (an example of a test cross, aa X Aa) we will have:
50% aa offspring (desired phenotype), and 50% Aa offspring.

Do you see what is happening here? Using this method of crossing to an Aa clone mother, we can NEVER have ALL the offspring showing the desired phenotype! Never! Never ever ever! Never!! LOL

The ONLY WAY to have all the offspring show a Aa phenotype is to cross an AA individual with an aa individual- all of the offspring from this union will be the desired phenotype, with an Aa genotype.

Now, all of that was for a Aa genotype for the desired phenotype. It isn't this complicated if the trait is AA or aa. I hope this causes every one to re-evaluate the importance of multiple backcrosses- it just doesn't work to stabilize the trait!

Also- that was all for a monogenic trait! What if the trait is controlled by a polygenic interaction or an epistatic interaction- it gets EVEN MORE complicated? AARRGH!!!!

Really, there is no need to do more than 1 backcross. From this one single backcross, as long as we know what we are doing, and grow out enough plants to find the right genotypes, we can succeed at the goal of eventually stabilizing most, if not all of the desired traits.

The confusion arises because we don't think about the underlying biological causes of these situations- to really understand this; we all need to understand meiosis.

We think of math-e.g. 50% G13, 50% hashplant

Next generation 50% G13 x 50% g13hp or (25% G13, 25%HP)

We interpret this as an additive property:
50% G13 + 25% G13 +25% HP = 75% G13 and 25% hashplant

This is unfortunately completely false- the same theory will apply for the so called 87.%% G13 12.5% HP next generation, and the following 93.25% G13, 6.25% HP generation; we'd like it to be true as it would make stabilizing traits fairly simple, but it JUST DOESN'T work that way. The above is based on a mathematical model, which seems to make sense- but it doesn't- we ignore the biological foundation that is really at play.

I hope this was clear, I know it can get confusing, and I may not have explained it well enough- sorry if that is the case, I'll try to clear up any questions or mistakes I may have made.

Have fun everyone while making your truebreeding varieties, but just remember that cubing (successive backcrosses) is not the way to do it!

-Chimera

 

[Yard dog]

Was it having opinions on things you know nothing about that made you the King of Cardboard harry?

Yard Dog: People always want what they cannot have. If everyone loved RKS so much why are there no cuts of it still around? Because as a community it wasn't deemed worthy of keeping. You doubt that people want RKS because of the stink? Exactly what trait do you think the line had in it that people do want? I've noticed that most of the people who do want it never had it to begin with so they're really basing it on stories. And the only stories I see about it are that it reeked. Roll through some Chem hybrids and you can get some stinky burning tires sprayed with skunk smells along with effects that people want these days.

True that people want what they cannot have or that cannot be bothered to do themselves, though I find the community always assumes others will keep things around, though I don't imagine all the busts helped with it?. The stink is exactly what they want, because they associate that stink with something in their minds be that from stories or what they remember from younger days.