Heritability of Intersex Traits

[GMT]

well to be a part of something you dont believe in is what? selling out or merely being a hypocrit? I guess if youre truly asking which part I am, I'm the part proud to be in the other section from smarmy jumped up sanctamoneous smart arses who feel anyone not kissing the right arses is harming the community.

I'm a hobbiest, but the worst sort from your perspective, I read and I breed. If you want to knock me for it, come over to my thread to do it.

 

[englishrick]

hay GetItReal

would it be cool for me to make S1`s and send them out as freebies,,,,or maybe SK1 x SK1 [fem outcross],,,,or am i doing our comunity an injustice?....i was gona genomicly test everything,,at that point i was planning to drown the untested seeds,,,is this not cool?

 

[englishrick]

I'm a hobbiest, but the worst sort from your perspective, I read and I breed. If you want to knock me for it, come over to my thread to do it.

nahhh,,,,i dont think your the worst type,,,,,,,,the hobbist who sells 1000`s of seeds is the worst type,,,,,,when have you sent seeds out of your controled enviroment?,,,,your the right sort of hobbist imo GMT,,,,you read and breed and dont taint

 

[GreenintheThumb]

I'm a hobbiest, but the worst sort from your perspective, I read and I breed. If you want to knock me for it, come over to my thread to do it.

No way, the worst kind are the ones who charge big money for the same quality of work you accomplish in your closet. You aren't the worst. Your seeds aren't flying all over the net to thousands of gardens across the world.

 

[englishrick]

^^^^ yeh man,,,

the hobbist who collects genotypes and maintains his collection without tainting our global genepool,,, is exactly the sort of hobbist i want to defend!!

you have your own genepool GMT,,,,i for 1 would defo go fishing in your pond,,,your the man with the polyploid ,,i wouldnt mind growing one of you specials,,,

 

[gettitreal]

GMT. Lets try something constructive. Why dont you provide your point of view on the heritability of intersex traits?

 

[englishrick]

hay GetItReal do you think cannabis is an X/Autosome dosage type?,,,thats how Ainsworth discribes it

 

[GMT]

I thought I had done, care to discuss it or put your own counter theory over? no? fair enough, but no need to get in my face anymore, you're a newbie with no gallery, no proof you are even a part of the scene, for all I know you're a kid with google. And look at your behaviour towards me, what would it look like to you in my position?

 

[englishrick]

can anyone list the main causes of sterility?

 

[GreenintheThumb]

hay GetItReal do you think cannabis is an X/Autosome dosage type?,,,thats how Ainsworth discribes it

I'd love your take on the matter as well.

 

[englishrick]

here is something i wrote in another thread,,,,see what you think of this Green bro,,,please tell me if im wrong or off the mark or something

good to see you bro..

im sorry frank, ,,,i dont quite understand what your sayin,,,,but im sure we can figure it out together,,,



the point i was trying to make is that Ainsworth describes sex determination in Cannabis as using "an X/autosome dosage type"



but let me please expand on what ive allready said

Once recombination has been suppressed in a chromosomal region, the proto-type Y chromosome will gradually accumulate deleterious mutations by a process known as Muller's ratchet (Muller, 1964 Felsenstein, 1974)

suppression of recombination spreads to the entire Y chromosome!!,,,once recombination is suppressed around the sex determination region, an incipient Y chromosome starts to differentiate

^^^an thats just part of the evoloution of sex chromozones,,,,eventualy the Y chromosome is lost, and X-to-autosome ratio sex determination system has evolved

according to Ainsworth this has alleady happend with cannabis!!

cannabis has Heteromorphic sex chromosomes!!! (Parker, 1990),,,sex chromosomes do not appear suddenly in animals or plants. rather, it is the pair of autosomes bearing the sex determination genes that have evolved specialized features,,,,basicly the degeneration of the Y chromosome, resulting in heteromorphy that became the hallmark of sex chromosomes..

severe degeneration of the Y chromosome causes loss of function for most genes. deletion of nonfunctional DNA sequences results in shrinking of the Y chromosome in size

two major sex chromosome systems have evolved. One is the active Y chromosome system, or the XY system in which females have two of the same kind of sex chromosome (XX),,,, while males have two distinct sex chromosomes (XY),,, The other is the X-to-autosome balance system, in which the ratio of X:A chromosomes determines sex by an X chromosome counting system and the Y chromosome is dispensable.

sex chromosomes in dioecious plants evolved as a mechanism for ensuring outcrossing to increase genetic variation ,,an this "Sex specificity" has evolved via male sterile or female sterile mutations,,,,stamen and carpel development involve large numbers of genes at various developmental stages, and mutations of any of the many regulatory genes could trigger abortion or loss of function of male and/or female organs (Wellmer et al., 2004),,,,.

suppression of recombination is a pivotal event in sex chromosome evolution... without suppression of recombination, the male sterile or female sterile mutations could revert to hermaphroditism,,,

 

[GreenintheThumb]

I'm not an expert of this stuff. Seems to me you still have trouble explaining your point in simple language. Or lets just say that post doesn't read much like your others, not that there's anything wrong with that.

As far as Ainsworth...well when did he make the judgment that cannabis was an X/Autosome type? I assume before the sex linked markers were found but i'm not sure.

It's my understanding that it's difficult to differentiate the X from the Y cytologically. I believe the Y is also slightly larger than the X for cannabis. So it's not fitting into the X/Autosome ideal evolutionarily. You also mentioned in this process that suppression of recombination spreads to the entire Y chromosome. We know this hasn't happened yet. Have you read this paper: Sex-linked AFLP markers indicate a pseudoautosomal region in hemp?

Peil, A., H. Flachowsky, E. Schumann, and W. E. Weber. 2003. Sex-linked AFLP markers indicate a pseudoautosomal region in hemp (Cannabis sativa L.). Theoretical and Applied Genetics

 

[englishrick]

correct me if im wrong, but it seems to fit into the accumulation of transposable elements and the duplication within the male-specific region stage ,this is when we see the expansion of DNA content on the Y chromosome....

the non-recombining region spreads to the majority of the Y chromosome and further "degeneration" occurs...at this stage the X and Y chromosomes are heteromorphic and the Y chromosome is physically larger than the X chromosome....


Ainsworth said Cannabis is using an X/autosome dosage system in [2000],,"i think",,,,,

i cant read that paper you mentiond because i need to join to access it,,,il search around an see if i can find a pdf for free somewhere

 

[GreenintheThumb]

correct me if im wrong, but it seems to fit into the accumulation of transposable elements and the duplication within the male-specific region stage ,this is when we see the expansion of DNA content on the Y chromosome....

How do you know? And these evolutionary ideals as to how this all happens doesn't always match up perfectly with reality. But what evidence do you have of any of this? Just that they Y is bigger?

the non-recombining region spreads to the majority of the Y chromosome and further "degeneration" occurs...at this stage the X and Y chromosomes are heteromorphic and the Y chromosome is physically larger than the X chromosome....

I just listed a genetic study that proves that the non recombining region has not spread to the majority of the Y. You realize a PAR region is recombining, yes?

Ainsworth said Cannabis is using an X/autosome dosage system in [2000],,"i think",,,,,

Well I haven't read his specific study. What methods did he use to come to the X/autosome conclusion? And obviously the sex linked markers study was 3 years after 2000....

 

[englishrick]

studies on the male-specific region have led to refined models of sex chromozone evoloution [Jablonka and Lamb, 1990,, Charlesworth, 1996,, Charlesworth and Charlesworth, 2000,,, Charlesworth et al., 2005]

correct me if im wrong??,,, but based on the most recent data??, sex chromosome evolution might be divided into five stages

1) a male sterile or a female sterile mutation occurs on a chromosome and recombination is suppressed at this locus and its immediate neighboring region leading to initiation of the "degeneration" process

2) suppression of recombination spreads to additional linked loci that lead to the "degeneration" of a small chromosomal region and the formation of a male-specific region on the primitive Y chromosome...the loss of gene content is sufficiently extensive to cause lethality of the YY genotype even though the primitive sex chromosomes still appear to be homomorphic at the cytological level. the papaya sex chromosomes are at this early stage.

3) the accumulation of transposable elements and the duplication within the male-specific region cause the expansion of DNA content on the Y chromosome...the non-recombining region spreads to the majority of the Y chromosome and further degeneration occurs.

at this stage, the X and Y chromosomes are heteromorphic, and the Y chromosome is physically larger than the X chromosome,, the Silene sex chromosomes possess these properties....

4) severe degeneration of the Y chromosome causes the loss of function for most genes and this enables deletions of the non-functioning Y chromosome sequences to result in shrinking the Y chromosome in size.

it is also possible that some sex chromosome systems would not have this phase of shrinking in size but would continue to expand and degenerate until stage 5 when the Y chromosome got lost..... in either case, a small portion of the sex chromosomes is still recombining to keep the X and Y chromosome pair together....

5) suppression of recombination spreads to the entire Y chromosome...further reduction in size of the Y chromosome and complete loss of the recombining pseudo-autosomal region occur.... the Y chromosome is totally lost and sex determination is controlled by X to autosome ratio.... a new Y chromosome might evolve, but it would have no effect on sex determination...

?

 

[englishrick]

check it out bro,,,,reviewed ,,,[Ainsworth 2000],,,http://aob.oxfordjournals.org/cgi/reprint/86/2/211.pdf


In cases where a sex chromosome system operates, it is clearly much more likely both that linkage will be found and that the linkage will be with maleness, as in all cases where the presence of sex chromosomes has been clearly established, the males are the
heterogametic sex. In plants such as Silene latifolia, Cannabis sativa, Phoenix dactylifera and Rumex acetosa, therefore, it is not surprising that male-associated markers are relatively abundant. In dioecious plants where sex chromosomes have not been identi®ed, markers for male-ness indicate either the presence of sex chromosomes which have not been distinguished by cytological methods or that the marker is tightly linked to a gene involved in sex determination.


"Di€erentiated sex chromosomes have been established clearly in only six families, representing about eight species and two major species groups. In the Cannabidaceae, which comprises three species only, Humulus lupulus (the culti-vated hop), H. japonicus and Cannabis sativa, all are dioecious and have evolved sex chromosomes of the X/autosome dosage type (Jacobsen, 1957; Parker, 1990)."

In a number of dioecious species, including Mercurialis annua (Durand and Durand, 1991), Cannabis sativa (Mohan Ram and Nath, 1964), Spinacia oleracea (Sherry et al., 1993), and Humulus species (Shephard, 1999), the divergence of the male and female developmental pathways occurs extremely early in foral development and the inappropriate organs are not initiated; in all these species the male owers resemble perfect fowers whilst the female owers are strikingly di€erent. In most species, however, both sets of sex organs are initiated and the inappropriate set of organs develops to some extent before abortion.

 

[GreenintheThumb]

I don't think much of a purpose is served in speculating on the evolution of sex chromosomes. No one's sure about it and in many ways they look at the issue backwards. I found the same problem with many proponents of evolutionary psychology. It's not always useful to make assumptions about real life things through a poorly understood dogma. Regardless, it looks to me like cannabis is firmly at what you call the third stage.

Like I said the Ainsworth article was before the one I mentioned. And the data about cannabis you list in these paragraphs is even older: 1964, 1990, and 1957.

I'm going with the recent stuff: cannabis is an XY system.

 

[englishrick]

im not disputing that cannabis is heteromorphic,,,,i firmly agree cannabis is heteromorphic!!

Charlsworth et al 2005 reviews evidence that recombination suppression occurs progressively in evolutionarily independent cases, suggesting that selection drives loss of recombination over increasingly large regions,, they discuss how selection during the period when a chromosome is adapting to its role as a Y chromosome might drive such a process.

In the first place, isolation caused by the cessation of recombination is a necessary condition for genetic divergence between the two sex chromosomes to begin....[Chalesworth et al 2005]

Transposable element accumulation is probably an early effect of restricted recombination, so one of the first changes affecting sex chromosomes may be increased DNA content.

cannabis seems to fit into the five stages, even an increese in size of the Y is indicitive............But is cannabis working entirly on an Active Y system, Green bro?,,,yeh it heteromorphic,, but is it working on an active Y?,,,,,have we seen direct conformation of an Active Y system?

if Y-linked genes are incessantly evolving to improve male function and compete with other male genotypes,,,, the changes may drive the evolution of recombination suppression, and thus recombination modifiers may also spread, some of which may themselves be on the Y (for instance, inversions).....

the five stages are from [Ray Ming5, Jianping Wang, Paul H. Moore and Andrew H. Paterson 2006]

i agree with you 100%,,,,,im just offering some insperration

i also think [according to the 5 stages], we do seem to be firmly at stage 3,,,,,,,,,,,i call it the "accumulation of transposable elements and the duplication within the male-specific region stage" ,,,,,,,,,,an this would explain the increese in size of the Y Chromozone,,,,

id just like to point out that "shrinking might never happen,,,the Y might continue to expand and "degenerate" until stage 5 when the Y chromosome is lost

the large chromosome size does not imply absence of genetic degeneration,, nor a high expressed gene content......the accumulation of repetitive sequences such as transposable elements on the Y does not necessarily imply degeneration.... it may just be a sign that recombination is rare...in recently evolved sex chromosomes, degeneration is probably much slower than in neo-Y chromosomes. there is less opportunity for selection to cause reduced effective population sizes

 

[GreenintheThumb]

Boy that's a lot of speculative bullshit that doesn't really further anything having to do with cannabis. Way to go...

"it may just be a sign that recombination is rare"
>>>>>> It isn't rare, read the study I showed.

There's male markers on the Y chromosome. Why not assume it's an active Y? What evidence is there of an X/autosome situation?

 

[GMT]

If an active Y which contains maleness is the mechanism by which the male parts of a plant are made, then again I ask where that info comes from in a female treated with chems to force the maleness to express itself.