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Doubled haploids
- Thread starter mofeta
- Start date
Hi Tom, Is my maths out or have I got this right:
each DH has 46 combos (assuming recombination is stopped)
But each one (without dna testing) may need 95 crosses to find the perfect match assuming no duplications and 96 seeds to work with.
Making 1% ish the perfect result.
Of course after that its plain sailing to perfect replicas every time (again providing recombination is always prevented.
each DH has 46 combos (assuming recombination is stopped)
But each one (without dna testing) may need 95 crosses to find the perfect match assuming no duplications and 96 seeds to work with.
Making 1% ish the perfect result.
Of course after that its plain sailing to perfect replicas every time (again providing recombination is always prevented.
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Hi GMT yeah 1% may be a more accurate figure. I have not crunched the probability maths so much other than to be excited about the relatively low numbers required. I believe 98 brings P=99%. Here is a handy chart http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2784905/table/tbl1/ from http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2784905/
wrongwrong
Member
have to run now... I'm guessing it is haha
fascinating stuff guys, just so i know i am following this....
we can take an elite clone, reverse it to get pollen, then use tissue/anther culture to create a doubled haploid plant.
then if you make S1 seeds of the DH you will have a true- breeding seed version of the elite clone?
am i on the page or should i go back and school myself some more?
VG
we can take an elite clone, reverse it to get pollen, then use tissue/anther culture to create a doubled haploid plant.
then if you make S1 seeds of the DH you will have a true- breeding seed version of the elite clone?
am i on the page or should i go back and school myself some more?
VG
lol Tom, only you would consider those to be low numbers.
VG, elite, apply chem to prevent recombination, reverse, magic and grow haploid, poison it to get DH.
Grow almost a hundred more the same way, select one, reverse it, pollinate all others, grow one seed from each, (or if you have access to dna testing even easier), hey presto, parents identified to give you endless copies of elite.
VG, elite, apply chem to prevent recombination, reverse, magic and grow haploid, poison it to get DH.
Grow almost a hundred more the same way, select one, reverse it, pollinate all others, grow one seed from each, (or if you have access to dna testing even easier), hey presto, parents identified to give you endless copies of elite.
Wow this thread just jumped up a couple levels! I'm impressed.
Hi Tom
Thanks for the link to the paper above:
Reverse breeding: a novel breeding approach based on engineered meiosis
That is the most concise, easy to understand paper I've read on the subject. I highly recommend it to anyone interested in the subject.
For those of you who do read it, look up and understand every term you don't know. It could take a long time, but when you are done you will have learned a LOT.
Scientists do not employ strict terminology for looks, it is essential for doing science. The terms have very specific, precise meanings, folding a complex concept into a small package that can be dealt with by our feeble minds. You really just absolutely cannot understand the larger conceptual canvas without a firm understanding of each and every term.
When I first started out reading technical papers, it would take me days, weeks, even months and years to fully grasp one paper. There are papers from the truly grueling disciplines (physics, math etc.) that I have been reading for years and I still don't fully comprehend them. It is worth it though, as the terms used in a specific discipline are finite- so after you spend a couple weeks plodding through your first genetics papers, the next one will only take a few days, and then after you read enough, you get it as soon as you read it.
Remember, you aren't reading a novel or a newspaper article. I can read those types of things at close to 1000wpm. In a technical paper (especially in a discipline I'm unfamiliar with) that can drop to a sentence a day. I never proceed past a word I don't grasp, and with a word that encapsulates a complex concept, I might have to read tens of thousands of words from textbooks etc to really understand the word.
One thing to look out for though is that a term that has a certain meaning in one discipline may have a different meaning in another discipline, so make sure you look up the term in the correct context.
The one thing that doesn't change though is the math. It is universal and is the epitome of the "conceptual packaging" I mentioned above. For the stuff we are talking about on these boards, I recommend a focus on statistics. Having a good grasp of stats unlocks the meaning of many a important scientific concept.
Once again, I am really impressed with the level of discourse on this thread, thanks to everyone for your thoughtful contributions.
Hi Tom
Thanks for the link to the paper above:
Reverse breeding: a novel breeding approach based on engineered meiosis
That is the most concise, easy to understand paper I've read on the subject. I highly recommend it to anyone interested in the subject.
For those of you who do read it, look up and understand every term you don't know. It could take a long time, but when you are done you will have learned a LOT.
Scientists do not employ strict terminology for looks, it is essential for doing science. The terms have very specific, precise meanings, folding a complex concept into a small package that can be dealt with by our feeble minds. You really just absolutely cannot understand the larger conceptual canvas without a firm understanding of each and every term.
When I first started out reading technical papers, it would take me days, weeks, even months and years to fully grasp one paper. There are papers from the truly grueling disciplines (physics, math etc.) that I have been reading for years and I still don't fully comprehend them. It is worth it though, as the terms used in a specific discipline are finite- so after you spend a couple weeks plodding through your first genetics papers, the next one will only take a few days, and then after you read enough, you get it as soon as you read it.
Remember, you aren't reading a novel or a newspaper article. I can read those types of things at close to 1000wpm. In a technical paper (especially in a discipline I'm unfamiliar with) that can drop to a sentence a day. I never proceed past a word I don't grasp, and with a word that encapsulates a complex concept, I might have to read tens of thousands of words from textbooks etc to really understand the word.
One thing to look out for though is that a term that has a certain meaning in one discipline may have a different meaning in another discipline, so make sure you look up the term in the correct context.
The one thing that doesn't change though is the math. It is universal and is the epitome of the "conceptual packaging" I mentioned above. For the stuff we are talking about on these boards, I recommend a focus on statistics. Having a good grasp of stats unlocks the meaning of many a important scientific concept.
Once again, I am really impressed with the level of discourse on this thread, thanks to everyone for your thoughtful contributions.
One more thing-
Once you read the paper Tom linked to, you might want to read about recent advances in this area.
Here is a link to a thread I made some time back that discusses them:
cenh3 null mutation for Cannabis?
I never finished the thread, because the view count was too low to justify the work involved, but the links to the papers are in the thread.
Once you read the paper Tom linked to, you might want to read about recent advances in this area.
Here is a link to a thread I made some time back that discusses them:
cenh3 null mutation for Cannabis?
I never finished the thread, because the view count was too low to justify the work involved, but the links to the papers are in the thread.
wrongwrong
Member
this is the patent to go with that paper
http://www.freshpatents.com/Reverse-breeding-dt20060810ptan20060179498.php
and I like how wijnker terms it;
http://www.freshpatents.com/Reverse-breeding-dt20060810ptan20060179498.php
and I like how wijnker terms it;
Back when my parents were attending university, the elucidation of the structure of DNA was brand new. Even the simplest understanding of the genetic code did not exist.
The highest level of understanding of the mechanisms of heredity was the field of cytogenetics (The branch of biology that deals with heredity and the cellular components, particularly chromosomes, associated with heredity. def from TFD).
I find that today, the emphasis on DNA/molecular genetics makes for students that are lacking in the understanding of this field.
It is not unusual to talk to a student that can tell you all about codons, initiator elements, transcription bubbles etc, but can't tell you what these images are:
The highest level of understanding of the mechanisms of heredity was the field of cytogenetics (The branch of biology that deals with heredity and the cellular components, particularly chromosomes, associated with heredity. def from TFD).
I find that today, the emphasis on DNA/molecular genetics makes for students that are lacking in the understanding of this field.
It is not unusual to talk to a student that can tell you all about codons, initiator elements, transcription bubbles etc, but can't tell you what these images are:
Attachments
wrongwrong
Member
is it an inversion loop off the top of my head it shows 2 nonrecombinants (as it states..) one is mutated? I think the other 2 imbalanced ones show a half of the original each? but I let myself down on this sort of thing.. up on breeding practices and that but this stuff gives me headaches at times!! last one like double cross over.
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Nunsacred
Active member
That's the general gist of it, yes.
Once you've made your DH plants, you still have to select good performers from them.
But this is (supposedly) really easy in DH populations because :
"by choosing a great pheno from DH plants you're also choosing a great parent at the same time."
Without falling into any jargon, that's the theory.
It's a big deal.
However, things aren't that simple in reality, mainly because there is much more to a ganja plant embryo than the presence of 0,1 or 2 copies of the n=10 haplotype.
Or (and let's go ahead and butcher it up some for simplification purposes), from you, we can recreate your parents. Not exactly, what we are really recreating is possible inputs your parents may bring when coupled. As we know, your parents when coupled are much more likely to give birth to many other combinations (siblings) before recreating you again. However, (if your parents were cannabis) rifling through 98 (various possible outputs, in my understanding), we will be successful 99% of the time, in recreating you, precisely. -T
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IE, I have nerd friends who are better at the maths than I seguro, and I am guilty of merely browsing over the material from time to time (though I occasionally speak the language that comes from meticulous review). But I do from time to time advertize myself as a decent translator and thus my question, are the maths in my head correct? That when we speak of X number of DH plants we are speaking of products, and not (haploid) inputs, in which case the numbers required become exponentially more demanding? Many thanks, it's truly refreshing to stick our junk on the guillotine from time to time to make sure we are on the same page sir. -T
wrongwrong
Member
would that not get you back to the 1 in 1000 (1024) odd shot? ie 2 to the power of N etc...
So I have it as if we were starting from scratch
say you're looking for something with 10 genes matched, in a diploid state you would need about 1 mil to see everything and select the one you want..
in a haploid state this would be 1024 (easily get down in numbers by disguarding all mutants, undiserable recessives etc etc)
but I'm guessing you would be doing this from some selfed lines.. so the numbers req'd would be a lot lower....
and then you are down to the 98 DH's
hmmm, before we get to counting stuff, does anyone know if what is required to prevent recombination in canna, has been identified and is available? I know for a bunch of stuff it has, but if its not done for canna, then the numbers are going to get much bigger.
Also where is the 98 coming from? I'm still only counting 96, seem to be missing 2 somewhere.
Also where is the 98 coming from? I'm still only counting 96, seem to be missing 2 somewhere.
Kopite, closer to strawberries than corn, ie we'll never get there (not where we are talking about) with traditional conventional breeding practices imo. I also believe I read the material correctly and that 98 outputs are what we are talking about, not so deep a search, as marveled by others (in the link I posted) as well as me.
hey Tom, thanks. With that being a probability chart rather than a stats counting chart, the 98 inputs give a 99% chance of success. (I just got up so may be thinking about this inside out still).
Think of a very large jar with an almost infinite number of marbles in it. Half are red and half blue. You are then given 2 more jars, and blindfolded. You have to put 10 blue marbles in 1 jar and 10 red marbles in the other jar. How many goes will you need to achieve it? Thats a harder task than we are actually discussing, as you only need the second jar to be filled with the opposite choices than the first jar ie if the first 5 picked in the first jar are red, and the second half blue, to get the desired marble combo, we only need to first pick 5 blues and then 5 reds to have the correct combo.
The chart says that in every 98 attempts, you have a 99% chance of getting it right once. A diff thing than, there are 98 variations. I'm still counting 96. I did half the maths and doubled
A system that does occasionally lead to mistakes, which is why I checked.
Think of a very large jar with an almost infinite number of marbles in it. Half are red and half blue. You are then given 2 more jars, and blindfolded. You have to put 10 blue marbles in 1 jar and 10 red marbles in the other jar. How many goes will you need to achieve it? Thats a harder task than we are actually discussing, as you only need the second jar to be filled with the opposite choices than the first jar ie if the first 5 picked in the first jar are red, and the second half blue, to get the desired marble combo, we only need to first pick 5 blues and then 5 reds to have the correct combo.
The chart says that in every 98 attempts, you have a 99% chance of getting it right once. A diff thing than, there are 98 variations. I'm still counting 96. I did half the maths and doubled
A system that does occasionally lead to mistakes, which is why I checked.
