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08-14-2013, 09:50 PM
So. . .this thread isn't about man/female stuff or money, or whatever but its a question that I figure someone here may have the answer to(there's a lot of smart people on this site)
So I was looking at something on down's syndrome, and how its pretty much due to some extra chromosomes or something. This causes the impairment etc etc. . .
So I was wondering . . .why isn't there something that is the OPPOSITE of that? like, an extra chromosome that gives someone like super smarts, strength, sight, pheromones or whatever.
I know this is kinda of a strange question, but I'm pretty sure someone smart lurks the forums here and could answer.
Just something I've been wondering heh.
Isaiah 4:1
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08-14-2013, 09:54 PM
It's a bit like asking:
I know that cancer can be caused from nuclear radiation, etc.
But why doesn't nuclear radiation ever do the opposite, y'know, give you super strength, speed, lazer vision, etc.
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08-14-2013, 10:05 PM
It's theoretically possible I suppose. Altered genotypes do cause altered phenotypes. But normally the most minute change in genotype produces massive changes in phenotype. Normal physiology and biology exists within a pretty narrow range, because I suppose one way of looking at it is just as one massive chemical reaction. If you change the conditions of the reaction, the most likely scenario would be a hugely deleterious effect.
Think of it as being a massive industrial chemical plant with hundreds of pieces of equipment involved. If you remove even one piece of equipment, probably the whole process shuts down. A random change in an industrial chemical plant like that might cause a favorable effect, but it's been designed to operate a certain way. The more likely scenario would be cascade failure.
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08-14-2013, 10:09 PM
Chromosomes have thousands of genes on them. When you duplicate an entire chromosome's worth of genes, a ton of proteins and metabolic pathways get thrown out of whack all at once, and the vast majority of these changes will be harmful, outweighing whatever small minority of the changes that might be beneficial. This is actually one of the main ways that evolution works - almost all gene mutations are harmful, but occasionally a helpful one will come along and be preserved by natural selection. That works when you're introducing novel mutations at a rate of 1 or 2 per generation--a small enough number to occasionally generate individuals with beneficial mutations who don't also have deleterious ones--but when you start duplicating thousands of genes at once at the chromosome level, the net effect is going to be very harmful.
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08-14-2013, 10:13 PM
During the evolution of a species the number of chromosomes also changes due to some random mutation.
But these beneficial random mutations that change the species for the better happen very rarely, and for every one mutation that brings positive character traits there are like a million mutations that bring negative ones.
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08-14-2013, 10:24 PM
Being born with a "Y" chromosone makes you smarter, stronger, faster and bigger.
You are definaely superior being born with a"Y" chromosone than not.
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08-14-2013, 10:28 PM
Damn, thanks for all the info, I learned a lot, especially from what gringochileno posted.
Maybe Roosh should open his own university.
Roosh V U
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08-14-2013, 10:39 PM
Quote: (08-14-2013 10:13 PM)Caveman Wrote:
During the evolution of a species the number of chromosomes also changes due to some random mutation.
But these beneficial random mutations that change the species for the better happen very rarely, and for every one mutation that brings positive character traits there are like a million mutations that bring negative ones.
This is a good rule of thumb.
Evolution finds local optimums, both in a mathematical and geographical sense.
Thus, any random deviances (mutations) will be much more likely to be deleterious than beneficial.
However, random positive mutations can indeed sweep through a human population very quickly.
Much more quickly than laymen, even ones cursorily familiar with evolutionary concepts, might realize.
In
The 10,000 Year Explosion, Cochran and Harpending note that a 7% initial selective advantage could result in most of a population having that trait after 6,000 years (page 135), in reflecting upon the ApoA-I
M mutation, which went from 1 copy to 43 in
ten generations in Italy.
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08-14-2013, 11:01 PM
I've been out of school 3 months and I've already forgotten everything... fuck.
To answer the OP: that kind of stuff happens pretty frequently in plants. Something will fuck up in reproduction and instead of having 2 sets of every chromosome it'll have 3 or something. Its believed that during mass extinction events stuff that has the most of something like a gene or even a chromosome duplication will be most likely to survive the event.
That being said I don't know exactly why it is not possible in humans. I would assume its because humans are much more complex than something like a plant. Altering one amino acid in one gene to something that has a slightly smaller side chain can fuck you up so bad you will get a disease and won't make it to your 5th birthday.
Silent mutations: even though silent mutations don't produce a noticable phenotype there is a difference between organisms in their G/C A/T contents as well as tRNAs. tRNAs aren't present in equal amounts so if you have a silent mutation and it uses a different tRNA to get the same amino acid it will have a higher 'evolutionary cost' and will be deleterious (but nearly unnoticable)
As for conserved sequences: they undergo a much lower rate of mutation because they are essential. Everything is fucked if you have even a slight change in the sequence. eg. histones (help in DNA coiling. DNA + Proteins = chromatin). if the sequence is changed so that the aa side chain is even one carbon less it will mess everything up and have disastrous results.
^^^ to the above
the sequence of amino acids is extremely important in the funcational part of a protein (ie. active sites of enzymes, protein channels). It is often specific down to a certain residue. a Histidine at aa 144 could create the necessary chemical and physical properties for an enzymes substrate to bind. Change that to a leucine at position 144 and you're screwed.
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08-14-2013, 11:14 PM
Yeah man Hox genes are nuts. They're highly conserved and determine anterior/posterior positioning of body parts. They're activated by various proteins/hormones. To much of one and you're going to grow a head where your ass should be.
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08-15-2013, 01:27 AM
Humans do not tolerate variation in chromosome number well. We have 23 pairs of chromosomes, 1 pair is our sex chromosomes, XY for men, XX for women. We have 22 pairs of autosomes. If a embryo is missing an autosome, it will terminate, humans cannot be monosomic(45 chromosomes resulting in one autosome missing), variation in sex chromosome number is often less severe and may lead to a "viable" fetus. Trisomy 21 is the most common form of down syndrome and it occurs from when instead of having 2xchromosome 21(autosome), the individual has 3xchromosome 21. Gene dosage is the reason problems are caused by the extra 21 chromosome, we are finely balanced biological machines, when things are thrown out of joint, there are many flow on effects, essentially chromosome variation is always very bad.