Something To Think About....

[Blimey]

So you chuck some pollen from plant A onto plant B......how many phenotypes can you expect to see from the offspring? .....not an easy question to answer.

Let's look at it another way.....

Cannabis Sativa has 10 sets of chromosome pairs.......so each parent has 10 sets of double-helix chromosomes in each cell. At the crucial moment when pollen hits pistil, and fertilization happens, each of those 10 pairs in each parent splits into two, and one gets passed down to the offspring.....

Let's look at those numbers.....for each chromosome pair, there are 4 combinations that can happen....

Parent A copy 1 - Parent B copy 1
Parent A copy 1 - Parent B copy 2
Parent A copy 2 - Parent B copy 1
Parent A copy 2 - Parent B copy 2

So with 10 chromosome pairs each splitting that way.....we have 4 to the power 10 possibilities = 1,048,576 possible variants.....and we are of course ignoring errors in the copying process, or mutations to any genetic material.

Puts "homozygous" and "heterozygous" in a new light, doesn't it?......and the number of seeds you'd need to grow out to see every pheno......

NB: The above number includes males, of course......it's only 524,288 combinations if you only worry about girls.....

 

[edgey]

and we're all trying to find that special 1

edgey

 

[schwilly]

9:3:3:1

I'm taking a genetics class right now. My mind is routinely blown.

Never knew the rabbit hole went that deep.

 

[Choc]

I thought about this the other day... lets say you have you 2 fav strains and want to cross them to get as much of that particular strain in to the other

assuming you can get seeds of both plant and they are quite stable IBL's and lets say we call them plant A and plant B

you pop all 20 seeds veg them up pull out any runts or weak looking babys and you are left with hopefully a 50/50 mix of males and females

m being male and f being female and mix them up like this

plants Af and Bm
plants Bf and AM

the offspring will be AB f1's and BA f1's

you then pop as many as you have room for and emulate what you done on the first grow

AB-f x BA-m = ABBA

BA-f x AB-m = BAAB

then

ABBA-f x BAAB-m = ABBABAAB

BAAB-f x ABBA-m = BAABABBA

and then lol

Put all ABBABAAB's and BAABABBA males and females in together and flower the lot.... the next and last lot of seeds you get if your super lucky you may get that 50/50 perfect cross strain you have been looking for

sorry to hijack your thread i was having a stoner day the other day and your post did what you said got me thinking

EDIT: with 1,048,576 possible variants its not as easy as i first thought to get all of 2 plants genetics into one

 

[dansbuds]

This is why i leave the breeding to the professionals !& I just

 

[Blimey]

I may have used the wrong terminology in my first post......the 1,048,576 is actually the number of genotypes that can occur in the offspring, rather than phenotypes.

Due to the phenomenum of dominance....any number of different genotypes will produce exactly the same phenotype, because some genes will always express in preference to others.

So....let's say the mother has a gene on both copies of the relevant chromosome that causes the pistils to turn a beautiful pink colour....if the father has a different version of this gene on both of his copies of the same chromosome that is more dominant, you'll never see the pink pistils, even though all of the offspring carry one copy of that gene, as the other gene will express in preference.

The father could have different copies of the gene on each chromosome, but if both versions were more dominant than the "pink" gene, you'd still not see pink pistils, because either gene variant from the father would still express in preference.

That's why we go to F2, to try and "line up" the chromosomal copies so that we can get F2 offspring that have the "pink" gene on both copies of the relevant chromosome.....

The reason good breeding is so difficult, is that each chromosome has tens or hundreds of thousands of genes on it.....so you aren't selecting for just one gene, you are selecting for every gene on that chromosome. Therefore, some combinations of traits simply can't be achieved.....you have to take the rough with the smooth. If the gene that gives you a 20-week flower period is also on the same chromosome as the "pink" gene, you have to select for both or neither of those traits.

 

[TB Gardens]

Nice bathroom read ;-)

 

[BlueGrassToker]

I think the consensus on the F1 generation is to expect a 1:3:1 ratio (maternal/mix/paternal).
I think you would need to have a rather large population to see this materialize. Maybe 200 or so. (shrug)

 

[Rusty420]

did you guys hear that 'whooshing noise'??

that was the sound of this thread going over my head..

lol, thanks for sharing..the numbers are enlightening!