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impeachme2
AmateurMycologist



Registered: 05/10/07
Posts: 646
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Artificial Evolution
#7695071 - 11/29/07 02:34 PM (16 years, 2 months ago) |
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Over time, do long lineages of home-grown mushrooms increase in size?
In nature, evolution of size wouldn't occur nearly as rapidly, because mushrooms that mature very small still sporulate just as well. In home grows, however, we force an artaficial evolution, that has happened with many species of fruit/vegetable crops, as well as livestock. We choose to take prints from fruits with desirable phenotypes, such as large size and fast growth rate.
Am I correct?
-------------------- tradelist
Edited by impeachme2 (11/29/07 02:36 PM)
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mycocurious
Mike O. Kuerias



Registered: 02/09/07
Posts: 1,265
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Re: Artificial Evolution [Re: impeachme2] 1
#7695244 - 11/29/07 03:17 PM (16 years, 2 months ago) |
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over time, yes. however mushroom cultivation - in general - is still in it's infancy as a whole...so we're still a long way away from that.
as a quasi-related piece of trivia...
I just learned recently that corn is a wholly man-made species through selective cultivation and breeding of a grass/grain called Teosinte by the Aztec indians thousands of years ago. If we (as a species) stopped planting corn, it would cease to exist on earth in less than five years...
Talk about a gift for the future, sown by our long-lost ancestors.
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Don't mistake my tone for a "matter-of-fact" attitude. I'm just presenting what I believe to be correct, until I'm corrected... - How Myco-Curious Prepares Coir & Compost Substrates - How Myco-Curious Builds A Bulk Humidifier - How Myco-Curious Builds An Automated Greenhouse ------------------------------------ figgusfiddus said: Keep in mind that inoculating or whatever in front of a flow hood won't help your bad substrate, your bad inoculant, your bad sterile procedure, etc. etc. etc. It's not a +3 flowhood of magic, it's just a tool.
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wortiesbo



Registered: 03/18/06
Posts: 866
Loc: new vegas
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Re: Artificial Evolution [Re: mycocurious]
#7696061 - 11/29/07 06:07 PM (16 years, 2 months ago) |
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you watched that show to eh mycocurious?
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Workman
1999 Spore War Veteran



Registered: 03/01/01
Posts: 3,598
Loc: Oregon, USA
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Re: Artificial Evolution [Re: impeachme2]
#7699440 - 11/30/07 02:59 PM (16 years, 2 months ago) |
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There is a fundamental difference between mushrooms and corn. When you say a long lineage I am assuming you mean growing a crop of mushrooms, taking prints and using those for the next generation, repeat.
The difference here between corn is that you are selfing ( breeding the mushroom with itself) instead of introducing new genes from another strain. This results, on average, in a 50% loss of genetic variability with each selfed generation. After about 6 or so generations there is less than 1% variability remaining so there isn't much to select for, barring helpful new mutations.
To use the corn model you would need to periodically cross spores from different strains to make varietal hybrids to introduce novel genes for later selection. Simply doing a series of multispore grows will only get you so far. Well distributed strains (B+, GT, etc.) that have been grown through several generations are already low in genetic variability and are poor candidates for selection by selfing.
I hope this makes sense.
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SuchSmartMonkeys
mycologically driven individual



Registered: 10/26/05
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Re: Artificial Evolution [Re: Workman]
#7722329 - 12/05/07 10:43 PM (16 years, 1 month ago) |
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yeah! what workman said! also, to the original post, you said it yourself...home cultivation requires the creation of a perfect environment that is man made. who is to say that these mushroom strains that are created within home cultivation could survive in nature, and thus, would only last as long as human proliferation occurred.
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fastfred
Old Hand



Registered: 05/17/04
Posts: 6,899
Loc: Dark side of the moon
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Re: Artificial Evolution [Re: Workman]
#7725364 - 12/06/07 05:06 PM (16 years, 1 month ago) |
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Quote:
Workman said: The difference here between corn is that you are selfing ( breeding the mushroom with itself) instead of introducing new genes from another strain. This results, on average, in a 50% loss of genetic variability with each selfed generation. After about 6 or so generations there is less than 1% variability remaining so there isn't much to select for, barring helpful new mutations.
Well distributed strains (B+, GT, etc.) that have been grown through several generations are already low in genetic variability and are poor candidates for selection by selfing.
I agree with the last part, but I'm not sure I agree with the first part.
50% loss of genetic variability is kind of a misleading term. It's a 50% decrease in heterozygosity. The Hardy-Weinberg law states that reproduction alone (without selection) does not alter allelic frequencies.
So there is really no loss in genetic variability in the absence of selective pressure, only the ratio of heterozygotes to homozygotes decreases. The frequency of alleles is not changed, therefore nothing is lost.
Given selective pressure and genotypes that are selectable for, you can quickly reduce the frequency of specific alleles. But given the fact that todays strains are already highly inbred and that most of the selective pressure is, and has for a long time been, of the same type you are going to have a situation of essentially random mating.
What I'm saying is that given the fact that the genetic variation is already pretty low, and that the alleles that are commonly selected for are already going to be homozygous in your starting germplasm you really aren't going to have any selective pressure for or against any of the alleles in your population and therefore are going to end up increasing homozygosity, but not changing the allelic frequencies and as such are not really going to lose any genetic variation.
-FF
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Workman
1999 Spore War Veteran



Registered: 03/01/01
Posts: 3,598
Loc: Oregon, USA
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Re: Artificial Evolution [Re: fastfred]
#7733723 - 12/08/07 03:31 PM (16 years, 1 month ago) |
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For simplicity, I used the less accurate "genetic variability" instead of heterozygosity.
I am not a geneticist but its my understanding that Hardy-Weinberg only applies to large populations and is violated with inbreeding and small populations size.
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fastfred
Old Hand



Registered: 05/17/04
Posts: 6,899
Loc: Dark side of the moon
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Re: Artificial Evolution [Re: Workman]
#7734498 - 12/08/07 07:43 PM (16 years, 1 month ago) |
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Part of Hardy-Weinberg is that reproduction alone doesn't alter allelic frequencies. In other respects most parts do only apply to populations and random mating. Inbreeding is a specific case of non-random mating, which is where the formulas come from that state heterozygosity is reduced by half each generation.
With each selfing you get 1/4 AA, 1/2 Aa, 1/4 aa Then G2 you get 3/8 AA, 1/4 Aa, 3/8 aa And so on with heterzygosity reduced by half each time, but no change in allelic frequencies of the population.
That makes it a lot quicker to reduce variation if your choosing lines, rather than maintaining even a small population. The more homozygotes there are the more likely you'll choose one in a line and end up immediately eliminating the other allele entirely.
-FF
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vdlsar
Stranger
Registered: 11/10/07
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Last seen: 11 years, 12 days
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Re: Artificial Evolution [Re: fastfred]
#7771790 - 12/17/07 09:37 PM (16 years, 1 month ago) |
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I wouldn't call it artificial evolution. It's just another form of selection. Humans happen to be incredibly complex animals and so the selection forces we apply are similarly complex (in this case, selecting for a trait that the rest of nature cares little about).
Humans have an urge to set ourselves apart from the rest of nature and talk about our actions as being "unnatural" as if we somehow rise above the mundane physical forces of the universe. We see how complex our own behavior is and this makes us egotistical and proud, but we forget that "dumb old nature" is actually what created us in the first place. I think we put ourselves on quite too high a pedestal.
Sorry for veering off topic.
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Slimz
.-~*´`*·~-experience-~*´`*·~-.




Registered: 10/03/07
Posts: 3,588
Loc: Maryland
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Re: Artificial Evolution [Re: vdlsar]
#7776699 - 12/19/07 08:13 AM (16 years, 1 month ago) |
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Humans happen to be incredibly complex animals and so the selection forces we apply are similarly complex (in this case, selecting for a trait that the rest of nature cares little about).
We are natural beings.. and when it comes to mushroom selection.. its no different than corn.. one day we may end up with a shroom that colonizes VERY fast, has HIGH psilocybin levels, is BIG, etc... we already have big fruits and fast colonizers.. someone should work on potency...
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