The determinator of sex

[DemonPigeon]

Is it possible cannabis is in the middle of evolving dioecy from monoecy and is not finished the process yet?

I'd agree in principle that we could observe this is happening in some populations, (I think we may be closer to androdioecy in some landrace S.E. Asian Sativas) although it's important to point out that obviously evolution follows no plan, it's dynamic and ever shifting towards what provides the most apparent benefit in various local circumstances.

 

[Tonygreen]

Going back a bit to the mentioned degeneration of the Y chromosome, here is an interesting paper.

ftp://biomol.univ-lyon1.fr/pub/cours/marais/Aline/Marais_CurrBiol08.pdf

"Y-linked genes show a clear tendency to have lower expres-
sion levels than their X counterparts. Although it is not yet
certain that the difference represents reduced Y-linked ex-
pression (because expression data from outgroups are not
yet available), and although degeneration of Y-linked genes
might not always cause lower expression (because deleterious
mutations could alter expression in either direction), the
consistently lower expression of Y-linked genes is unlikely to
be adaptive, but suggests functional degeneration"

If this is true the Y may just clutter things and not be the best approach to breeding possibly a rudimentary tool at best.
Tom Hill has said some interesting things about breeding with females only.

Maybe females retaining the ability to produce pollen despite the presence of a Y chromosomes is an advanced evolutionary tool...

Understanding how all this works is probably a key breeding tool.

 

[GMT]

we can make men grow tits, but I only date women.

 

[BullDogUK]

And yes I wish the spell checker wasn't american here telling me there's no U in favour

Oh man, tell me about it

So why would we want to force something to happen unnaturally when we can sit back and let it happen naturally.

Well as I said, this is all hypothetical. Of course actually breeding like that would be completely impractical. I'm just getting at the point that females also contain 'pollen' genes or however you want to describe it.

But the fact that we have to force the females to do this, tells us they are absolutely different from males. Not just in expression, but in content.

Ok I think I understand your point now

to say that a female contains a male genotype is inaccurate. It contains the instruction sets (genes) to produce pollen sacks, but that's not saying the same thing.

Well alright, I will concede that they do not contain an identical genotype, I'm instead referring to the genotype regarding pollen sac production, which evidently females contain. So from this, I'd say that the differences in genotype between female and male are largely down to differences in gene expression regulation. But then we get to the big argument (I guess):

to refer to a female that produces pollen as the father or a male is inaccurate.

So referring to it as male is probably inaccurate as you say, which is why I've tried to use quotation marks where possible to show that it's simply filling the role. It's 'male' in the same way a politician is 'honest'. But I feel that referring to it as the father is correct. Pollen is the male gamete in plant sexual reproduction correct? So if we have plant A pollinated by plant B, disregarding genotype gender (maybe a better term to use?), the resulting offspring is going to have plant A as the seed producing, mother plant and plant B as the pollinating father plant. As I said, whether or not the pollen contains only X, only Y or a mix of the two is irrelevant as they are still filling the 'male' aspect of sex.

 

[DemonPigeon]

This is why in Marijuana Botany Rob Clarke sticks to "Pistillate and Staminate"

Whether a reversed plant is "still female" or has been made into a "male" we can say that it exhibits a "staminate phenotype"

 

[xmobotx]

yeah; 'male' and 'female' just as w/ electrical connections and plumbing fittings are slang terms when applied to plants

it facilitates ease of conversation until you get to the finer points

 

[Infinitesimal]

I am really busy for the next couple days... but this has been on my mind a little while and want to touch on it while relevant to the current convo... I'll respond to some others directly a little later...

This was a really great explanation GMT, cheers



I have a feeling we may be misunderstanding each other slightly here so I'll try and break down the points again as it just makes it easier to get each point across without confusing things... Saying that I feel we're in agreement here? As I mentioned before I think it seems likely (to me! I'm a n00b at cannabis everyone) that, as we can force the expression of pollen sacs in female plants, that the genes responsible are located outside of the Y chromosome, leading to the conclusion that the Y chromosome may be involved in up-regulating the synthesis of 'male' proteins or the down-regulation of 'female' proteins, leading to:



Well, if we can force a female to produce pollen, does this not mean that the genes responsible for the sex phenotype are present in both males and females? In this case both 'males' and 'females' are technically both male and female in genotype.

I made a simplified diagram derived from the little summary you made (comic sans for extra humor):

[URL=https://www.icmag.com/ic/picture.php?albumid=44503&pictureid=1070408&thumb=1]View Image[/url]

So in this model, the X chromosome silences/down-regulates the production of 'male' proteins, resulting in the loss of pollen sacs and pollen production. The Y chromosome, on the other hand, up-regulates this synthesis, enough to overcome the down-regulation of the X chromosome. You also mention silencing of female flower production which I forgot to add in >.< but yes, that also makes sense.

Either way, we know that females are capable of producing pollen sacs. Regardless of whether the pollen contains X or Y chromosomes, this will still lead to the production of fertile offspring, capable of a repeated 'maleized' female x female crossings correct? If this is the case, then this is what I mean by the distinction being somewhat irrelephant. Obviously in nature this isn't going to be a successful survival mechanism (thus why we see Y chromosome males I guess?).

co dominant silencing seems plausible...

a couple things...

first,

think about it this way... sex hormones... (XY) males have estrogen and testosterone... with the testosterone higher than the estrogen... the higher the T/E ratio the more manly, the lower the ratio the more feminine, a male is... conversely... females (XX) have both testosterone and estrogen with the estrogen being higher than the testosterone... the higher the E/T ratio the more feminine and sexy a women is... the lower the E/T ratio or when there is higher testosterone than estrogen in a women they end up very masculine and manly. (no she doesn't sprout nuts.. I explain that further on)

second,

correct me if I am wrong but doesn't the X chromosome contain more genes that the Y? if that is the case then I imagine the X contains all the info that the Y does and then some... so with the right hormonal cues (weather from natural stress or chemical induction) can produce male sexual organs on a female (XX) plant

the difference and the reason (XX) cannabis plants can't be exactly compared to sex in a human is because the female plant can produce male sex organs and... obviously (XX) female women cannot do this... but the reason is simple... cannabis only produces its sexual organs, expressing its gender traits, during sexual maturity (therefore production and development of the sexual organs in the cannabis plant are subject to hormonal influences)... opposed to humans who produce its sexual organs during gestation, thereby making it impossible for post natal hormonal fluctuations to effect the physical expression (development) of an individuals sexual organs the way it does in cannabis... though, hormonal fluctuations can effect the functionality of and the desirability to use ones sexual organs in humans...

so just because a female human can't sprout a dick, bust a nut and impregnate another female (as that is pretty extreme for a mammal) doesn't mean that the factors that determine the sexual expression of an individual aren't the exact same... genotype -(XX)-(XY)-(XX/XY)- the sex of the individual + environment based hormone fluctuations = gender expression.

I hope that was clear enough to understand...

Peace,
Infi

 

[Tonygreen]

I have read the Y chromosome has lots of "junk" dna in it.

 

[BullDogUK]

Human X and Y chromosomes are not the same as X and Y chromosomes found in cannabis I don't think? I really doubt it is anyway hehe

Concerning the genetic information found on the human sex chromosomes - In human females one of the X chromosomes is silenced very early in development.

http://en.wikipedia.org/wiki/X-inactivation

It's not something I studied so can't give you any real detail besides a wiki link but it should suffice

 

[GMT]

bulldog, i think we are now at a point where the differences in what we are saying is down to personal preference in language. So although i dislike calling females fathers, I can't argue that its wrong, only that I don't like it. I prefer DP's language, but will continue to use female even when its been reversed. personal preference only.
Infi, if an X contained ALL the info a Y did, wouldn't it try to silence itself? To my mind, the fact that XXY plants show male, demonstrates how much stronger the Y influence is than the X. But that stands to reason since every Y has to silence the effects of an X to show male, whereas the females have less of a battle on their hands. In mammals the X's are bigger, but in canna the Y's are bigger.

 

[BullDogUK]

i think we are now at a point where the differences in what we are saying is down to personal preference in language.

Completely agree mate! It's always nice to be able to have intelligent discussions with people though

In mammals the X's are bigger, but in canna the Y's are bigger.

Might be another misunderstanding of the language here - The X and Y chromosomes found in cannabis are not at all like the X and Y chromosomes found in humans/mammals. They have separate evolutionary lineages!

Look at it this way; when plants and animals finally became distinct from one another, no plants had XY sex chromosomes and I doubt (at that stage) that any animals had sex chromosomes we'd recognize.

 

[GMT]

doesn't chance the fact that the female sex chromosome in mammals are larger, whereas in cannbis they are smaller.

 

[BullDogUK]

Oh no for sure; just making sure that people are aware that cannabis XY are not the same as the things that we (collectively in this thread) know about the human X and Y chromosomes.

 

[auto guerilla]

we need a biologist on board for sure to clear things up. whish i was one right about now. it's all too confusing. facts are hard to find.???

 

[BullDogUK]

Do I not count?

 

[Sam_Skunkman]

Infinitesimal,
I agree with much you say except for:
"is it any wonder that a plant species can go from one that is a wild, non psychoactive, monoecious, fiber/seed producing plant."

Cannabis was wild, non-psychoactive, with fiber and very small seeds before man. It was not monoecious as far as I know. Cannabis is not naturally monoecious rather man has created and maintained monoecious varieties for hemp production.
same with:
"blocking the ethylene likely triggers the expression of latent monoecious traits buried in the cannabis genome... or at least maybe?"

I do agree that Cannabis may have well had a distant NON-Cannabis ancestor that was monoecious, but I see no evidence that all ancient Cannabis was monoecious.
-SamS

 

[3rdEye]

wonderful discussion on sex determination with cogent and clear points being delivered by the contributors. thank you for sharing this discussion with us.

I've been following along the debate mostly out of self interest. and i have a male plant that was male for 3 months and then, under 18 hr days, sprouted some pistillate hairs on the apical tips. I fertilized these with pollen taken from the same plant and now have around 10 seeds to work with. I also fertilized a female sibling with some of this pollen as well. I'm guessing that this is rather unstable, so i am not including this in my more organized plans at breeding, but i thought it of note since the male displayed no signs of intergender traits until well in to it's lifespan. It was also kept on 14.5 hr day length - the original "parent" plant.

 

[Only Ornamental]

...and i have a male plant that was male for 3 months and then, under 18 hr days, sprouted some pistillate hairs on the apical tips. I fertilized these with pollen taken from the same plant and now have around 10 seeds to work with...

Are you interested in supermales or why did you self-pollinate that male?


BTW I have just started reading this interesting thread but I'll wait with other comments until I've read it (+/-) all.

 

[Sam_Skunkman]

I suspect an inter-sex can be genotype or inter-sex can be just expression that is phenotype and maybe also needs environmental stress to inter-sex, I am not sure how you can tell the difference just by looking at them, maybe with testing. They both likely have a genetic basis, inheritable by progeny. I hope they find/develop DNA tests for inter-sex plants, maybe for both genotype and phenotype inter-sex like they already have for Male and Female genotype plants, the sooner the better.
Any ideas?
Colors like purple are controlled by genes and some plants will turn purple no matter what the temperatures are hot or cold, while other varieties will not turn purple unless the temperatures get below 30-50. So inter-sex is a bit like that.
I hope this is clear, I am getting old and my mind is getting feeble.
What I really want is a discussion of inter-sex and how to get rid of it or reasons why not.
Some growers/breeders believe that inter-sex plants can be used and some even believe that inter-sex plants are better in some ways. I do not. I think everything/anything you want from an inter-sex plant can be found in non inter-sexed plants without the baggage of passing on inter-sex traits to the progeny. A real problem is the small numbers of plants that breeders use to select from, that limits the selection of superior or elite inter-sex free plants to use for breeding inter-sex free progeny.
I will admit that through severe selection and several+ years of growing large numbers it is possible to pretty much eliminate inter-sex from a variety, I did it with my Durban Poison variety released by Sacred Seeds way back when....
So I guess I am saying it is possible to save wanted traits and use them without keeping or using the inter-sex part.
I would work with almost anything inter-sex or not, to get the terpene's and smells and tastes I am after.
-SamS

 

[Tonygreen]

Numbers. Selection.