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 undergrounder
Registered: 11/10/06
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Loc: NSW
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 Proton radiation and Evolution
#8533095 - 06/17/08 09:55 AM (3 months, 19 days ago) |
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Well I was reading my bible tonight (or watching i guess) and the great Lord 'Carl Sagan' told me that proton radiation ... (the stuff that flies through space as a result of exploding supernovas and can penetrate through rocks, mountains and entire planets. Oh and the same stuff that is responsible for the constant, low static picked up by Geiger counters) ... can affect organisms in a minor way, particularly by causing mutations. Take for example that recent finding of the bacterial mutation in an otherwise totally 'enclosed' experiment. He then went on to tell me that this kind of mutation could be responsible for significant, otherwise 'random' mutations in evolutionary biology. In this way, the advancement of life is inextricably connected to the cosmos 'billions and billions' of miles away.
I normally take everything Carl Sagan has to say as pure and objective truth, but i thought i'd check in to see what you guys think of that statement. Are mutations in evolutionary biology (at least in some small part) a result of 'star stuff' bombarding us from the other side of the universe?
My bible is Carl Sagan's 1980 documentary 'Cosmos' by the way.
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 RIP
Bigger and bolder and rougher and tougher in other words sucka there is no other...
   
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zouden
Neuroscientist
Registered: 11/12/07
Posts: 2,466
Loc: Australia
Last seen: 5 hours, 13 minutes
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Re: Proton radiation and Evolution [Re: undergrounder]
#8536279 - 06/18/08 05:54 AM (3 months, 18 days ago) |
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Of course. In fact, cosmic radiation can cause cancer. It's quite a remarkable thing to consider, you could be hit by a particle shot out of a dying star, and it'll turn your life upside down.
But most mutations aren't caused by cosmic radiation, they're caused by the inherent error rate of the DNA replication process.
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9/11 was sketchy but I mean come on
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DieCommie
Ally
Registered: 12/11/03
Posts: 6,442
Loc: The Union
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Re: Proton radiation and Evolution [Re: zouden]
#8537238 - 06/18/08 02:07 PM (3 months, 17 days ago) |
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What kind of radiation is DNA mutation most susceptible to?
I ask, because most radiation obviously comes from our sun. But he is talking about proton specifically.
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Behold yon miserable creature. That Point is a Being like ourselves, but confined to the non-dimensional Gulf. He is himself his own World, his own Universe; of any other than himself he can form no conception; he knows not Length, nor Breadth, nor Height, for he has had no experience of them; he has no cognizance even of the number Two; nor has he a thought of Plurality; for he is himself his One and All, being really Nothing. Yet mark his perfect self-contentment, and hence learn his lesson, that to be self-contented is to be vile and ignorant, and that to aspire is better than to be blindly and impotently happy.
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zouden
Neuroscientist
Registered: 11/12/07
Posts: 2,466
Loc: Australia
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Re: Proton radiation and Evolution [Re: DieCommie]
#8537638 - 06/18/08 04:13 PM (3 months, 17 days ago) |
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That's a good question. Gamma radiation causes breaks, which cannot be recovered, while UV radiation causes thymine dimers which can be recovered.
High energy cosmic radiation? I don't know, they didn't seem fit to cover it in my undergrad classes.
Note that unless the radiation hits your testes you won't pass the mutations on to your children.
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9/11 was sketchy but I mean come on
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 tripsis
biophile-misanthropist-doofer
Registered: 04/13/08
Posts: 3,826
Loc: Gondwana
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Re: Proton radiation and Evolution [Re: zouden]
#8539658 - 06/19/08 04:36 AM (3 months, 17 days ago) |
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So basically nudists are in the most trouble then.
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Since we depend on an abundance of functioning ecosystems to cleanse our water, enrich our soil and manufacture the very air we breathe, biodiversity is clearly not an inheritance to be discarded carelessly - Edward O. Wilson 1992
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johnm214
Registered: 05/31/07
Posts: 6,356
Loc: Americas
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Re: Proton radiation and Evolution [Re: zouden]
#8539701 - 06/19/08 05:06 AM (3 months, 17 days ago) |
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Quote:
zouden said:
That's a good question. Gamma radiation causes breaks, which cannot be recovered, while UV radiation causes thymine dimers which can be recovered.
High energy cosmic radiation? I don't know, they didn't seem fit to cover it in my undergrad classes.
Note that unless the radiation hits your testes you won't pass the mutations on to your children.
Well, UV radiation can do more than that. The stuff I'm aware of is all indirect, but its still the cause... UV rads can increase the reactive/oxized species in the cell and lead to genetic damage indirectly as well as through the dimers.
And single stranded breaks can also be fixed, as I'm sure you know, so its not like the UV induced dimers are necceasarily less harmful than ss breaks by other radiation. I know double stranded breaks can also be repaired, in mechanisms similar to the genetic crossover in meiosis, but are much more likely than ss breaks to lead to serious problems.
Just saying that I don't think thiamine dimers are neccesarily better due to damage control than ss breaks or whatnot due to error correction- though they may well be in the end, don't really know (we get taught so much about what can/does happen but less about what will/relative liklihoods of the processes, lol- at leas tin my experience.)
As for most mutations being caused by dna replication errors, do you have a source for that? I wonder if there's a net difference in the harm caused? Either way, you still need a combination of errors to lead to problems, but I wonder if there are any models or studies showing the risk of common carcinogens as compared to natural mutations? I really don't know if the rates are comparible.
Certainly replication errors are pretty rare on the kb scale, but there is a bunch of polymerase activity going on in the endothelial cells at most time, which are also the most heavily damaged from carcinogens to boot. hmmm...
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zouden
Neuroscientist
Registered: 11/12/07
Posts: 2,466
Loc: Australia
Last seen: 5 hours, 13 minutes
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Re: Proton radiation and Evolution [Re: johnm214]
#8539724 - 06/19/08 05:19 AM (3 months, 17 days ago) |
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I guess our germline cells are so well protected (at least they are for women) from the environment that they'd be one of the least likely cells to be affected by external mutagens. Even people with testicular/ovarian cancer probably don't always pass mutations on to their children, since not all of the tissue in the ovaries actually contain germline DNA.
I don't have sources for any of this, it's just idle speculation.
So the question is, when your child gets a mutation in her DNA that you don't carry (assuming you're the legitimate parent)... at what point did the mutation occur? Is it in your germline, or did it occur during recombination? Or perhaps at the zygote stage? In fact I'd say the zygote stage is the time when she'd be most susceptible to inherent mutations. There's a baseline mutation rate for cell division, but when she's an adult, a mutation in a single cell isn't very important, compared to when she's an 8-cell zygote.
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9/11 was sketchy but I mean come on
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Visionary Tools
Kiffah
Registered: 06/23/07
Posts: 2,933
Last seen: 1 month, 24 days
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Re: Proton radiation and Evolution [Re: tripsis]
#8539756 - 06/19/08 05:41 AM (3 months, 17 days ago) |
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Quote:
tripsis said:
So basically nudists are in the most trouble then.
Nudists have other things to worry about than various radiation.
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In times of universal deceit, the truth becomes a revolutionary act.
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johnm214
Registered: 05/31/07
Posts: 6,356
Loc: Americas
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Re: Proton radiation and Evolution [Re: zouden]
#8539836 - 06/19/08 06:43 AM (3 months, 17 days ago) |
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Quote:
zouden said:
I guess our germline cells are so well protected (at least they are for women) from the environment that they'd be one of the least likely cells to be affected by external mutagens. Even people with testicular/ovarian cancer probably don't always pass mutations on to their children, since not all of the tissue in the ovaries actually contain germline DNA.
I don't have sources for any of this, it's just idle speculation.
So the question is, when your child gets a mutation in her DNA that you don't carry (assuming you're the legitimate parent)... at what point did the mutation occur? Is it in your germline, or did it occur during recombination? Or perhaps at the zygote stage? In fact I'd say the zygote stage is the time when she'd be most susceptible to inherent mutations. There's a baseline mutation rate for cell division, but when she's an adult, a mutation in a single cell isn't very important, compared to when she's an 8-cell zygote.
by not carry, you mean its not in your somatic cells, not part of your overall genome?
The thing w/ women though is that they have a lifetime of ovaries sitting around. So lowlevel background carcinogenesis can be pretty signifigant.
Since make sperm constantly, with error correction possible for the germ cells in the meantime and when/prior to when they undergo their first mitosis in the process to producing sperm, but women have a lifetime of ova waiting to accumulate mutations, I'd say the women's ova would be the most likely culprit- especially in an older woman. You get one of those funky ova and good luck.
I'm sure that's why old women have a high rate of mutations in their offspring (nondisjunction probably doesn't count though).
So i'd have to say its most likely the ova get damaged during the womans life and lead to mutations in the offspring.
I guess during zygote stage there could be bad consequences lik eyou said, but the high error correction rate o f the polymerases would seem to take care of must mistakes. I wonder if there has been any studies on this? Probably hard to figure out where teh mutation came from, even if you could somehow collect rejected or whatever zygotes.
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zouden
Neuroscientist
Registered: 11/12/07
Posts: 2,466
Loc: Australia
Last seen: 5 hours, 13 minutes
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Re: Proton radiation and Evolution [Re: johnm214]
#8539878 - 06/19/08 07:02 AM (3 months, 17 days ago) |
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Yeah, we're only just getting to the stage where it's feasible to scan someone's DNA for mutations, let alone try and figure out where the mutation came from. In a decade or so, there'll be so much more information at our fingertips for this kind of study.
I like your theory on the ova sustaining damage. Perhaps that's why when women get pregnant after 40 there's an increased risk of things like Down's syndrome?
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9/11 was sketchy but I mean come on
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johnm214
Registered: 05/31/07
Posts: 6,356
Loc: Americas
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Re: Proton radiation and Evolution [Re: zouden]
#8539927 - 06/19/08 07:30 AM (3 months, 17 days ago) |
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Perhaps.
Since downs syndrom is just the two chromatids not seperating in meiosis, I don't know if this is really relevant to a discussion on genetic mutation.
I don't know why its correlated with age, but I'd imagine the cell itself could just be breaking down; perhaps the microtubules start sucking or something like that.
Still, I just checked wikipedia and centromere's are made of DNA too, so I guess nondisjunction could be an indicator of DNA health, perhaps, but I really don't know.
On a lark I searched for childhood cancer and maternal age and found this graph which showed a correlation in maternal age with risk of developing some type of leukemia or soemthing. There was one confounding factor mentioned in the abstract that I didn't understand though, cuz I didn't feel like reading the whole study
Quote:
Figure 2. Rate ratios for maternal age (reference group 28-31 yr) with corresponding 95% CIs, estimated using a maternal age–child birth cohort model. Maternal age classes are denoted by the first year. CCRP, 1980 to 1997.
http://cebp.aacrjournals.org/cgi/content/full/16/2/347
Maybe I'll look later and see if this is similar to other genetic diseases arising from genetic mutations
I bet this is totally a result of induced mutations too: since the mother's eggs are pretty constant through her life, I'd imagine the only thing that changes is how long the eggs are exposed to mutagenic things
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undergrounder
Registered: 11/10/06
Posts: 1,264
Loc: NSW
Last seen: 7 hours, 3 minutes
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Re: Proton radiation and Evolution [Re: johnm214]
#8543221 - 06/20/08 01:34 AM (3 months, 16 days ago) |
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wow... i didn't realise the convo would be so in-depth so thanks everyone!
so basically while proton radiation might affect you, other types of radiation would probably cause more mutations..
.. So going on the idea that some form of radiation caused the first 'mutation' of a living organism, then UV would be the more obvious candidate..
Just in a general sense, are genetic mutations required for evolution? Is that the way evolution 'happens'? and if so..
Could you say that apart from all the obvious things that support life (particular elements, proteins, complex molecules), that for life to evolve you also need a source of radiation?
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RIP
Bigger and bolder and rougher and tougher in other words sucka there is no other...
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johnm214
Registered: 05/31/07
Posts: 6,356
Loc: Americas
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Re: Proton radiation and Evolution [Re: undergrounder]
#8543253 - 06/20/08 01:53 AM (3 months, 16 days ago) |
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yep, evolution comes from mutations
No you really don't need radiation for evolution, but it may help, as their are many natural carcinogenic chemicals.
One thing to keep in mind is that almost every single mutation will be detrimental or of no consequence. Very rare to get something that is helpful.
I don't really know much about "proton radiation" so I"ll let others address that.
As for the first mutation, I really don't know.
If you mean the same thing tripsis asked, then I'd say its likely some chemical or simple mistake in the DNA reproduction machinery (such as in my avatar).
If you mean after the kid was born, I'd still say its more likely some random mutation from the rep. machinery causes the first mutation, but just a wild guess. Sunlight can certainly cause many, as can oxygen and oxygenated species.
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zouden
Neuroscientist
Registered: 11/12/07
Posts: 2,466
Loc: Australia
Last seen: 5 hours, 13 minutes
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Re: Proton radiation and Evolution [Re: johnm214]
#8543315 - 06/20/08 02:55 AM (3 months, 16 days ago) |
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Quote:
So going on the idea that some form of radiation caused the first 'mutation' of a living organism
That's probably not true, because simple DNA replication introduces mutations. It's not error-free.
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9/11 was sketchy but I mean come on
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undergrounder
Registered: 11/10/06
Posts: 1,264
Loc: NSW
Last seen: 7 hours, 3 minutes
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Re: Proton radiation and Evolution [Re: johnm214]
#8543380 - 06/20/08 04:23 AM (3 months, 16 days ago) |
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oh ok... i see... i could ask what causes those errors in the DNA process, i'm sure there's a simple and benign cause, but it's going off the point...
Anyway, as far as i've read, while evolution is the process of natural selection and passing down of adaptive traits, for there even to be a difference in the first place is the role of a 'random mutation'? (and where i use random, you could insert 'mutation - DNA induced, from radiation or otherwise)
Anyway another question.. This involves DNA, the theoretical creation of life in very simple organisms and the order in which this occurs.
First, what comes first, lifeor evolution.. It seems to me possible that you can have living things that don't evolve (ie: they self-replicate), but you can't have something that evolves without it being alive to carry out the process of natural selection.
Secondly, as far as i can tell, simple-cell division requries DNA. I don't know this, im just assuming that a self-replicating cell would need to read the instructions for replicating itself from DNA. It couldn't in effect take a picture of itself in its current state and then decide to replicate that. That process would require complexity and abilities that the simple cell wouldn't have. No, it must read how to build a copy of itself from reading its own DNA.
So the simplest self-replicating cell has DNA, but without necessarily evolving. BUT anything that DOES have DNA, which in turn is NECESSARILY open to mutations, be it chemical, radiation or otherwise, must be open to the forces of natural selection and evolution. Where there is DNA, there are mutations, and where there are mutations, there is evolution.
So evolution (packaged in DNA) comes BEFORE life. At the very least, The very first living thing that ever existed, must have both DNA, and the ability to replicate itself using that DNA. From that one cell comes every form of life that has ever been known.
But then the question, where did that very first simple strand of DNA come from, and what was its use? if not for replication? Does this mean that some non-living things have DNA? And if they do, what could they use it for, if they're not alive?
sorry i think i'm going somewhere with all this, but just help me out..
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RIP
Bigger and bolder and rougher and tougher in other words sucka there is no other...
Edited by undergrounder (06/20/08 04:30 AM)
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zouden
Neuroscientist
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Posts: 2,466
Loc: Australia
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Re: Proton radiation and Evolution [Re: undergrounder]
#8543436 - 06/20/08 05:15 AM (3 months, 16 days ago) |
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Quote:
Does this mean that some non-living things have DNA?
Yes, viruses have DNA, and they aren't living. Also, RNA probably came before DNA, and RNA has the ability to replicate itself even without any cellular machinery. So that's probably how the whole shindig got started.
As for your question about what came first: life or evolution... I'd say they both appeared at the same time and they are inextricably linked. Life is a product of evolution, and evolution is a feature of life.
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9/11 was sketchy but I mean come on
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tripsis
biophile-misanthropist-doofer
Registered: 04/13/08
Posts: 3,826
Loc: Gondwana
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Re: Proton radiation and Evolution [Re: zouden]
#8543443 - 06/20/08 05:23 AM (3 months, 16 days ago) |
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I was joking with my nudist comment...
Anyway, I would guess that evolution actually came first as evolution isn't restricted to life, e.g. the universe is constantly evolving but life (at least on earth) has been around for a finite time.
RNA possibly formed through chemical reactions alone, as it has been shown to be possible.
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Since we depend on an abundance of functioning ecosystems to cleanse our water, enrich our soil and manufacture the very air we breathe, biodiversity is clearly not an inheritance to be discarded carelessly - Edward O. Wilson 1992
Edited by tripsis (06/20/08 08:27 AM)
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undergrounder
Registered: 11/10/06
Posts: 1,264
Loc: NSW
Last seen: 7 hours, 3 minutes
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Re: Proton radiation and Evolution [Re: zouden]
#8543460 - 06/20/08 05:46 AM (3 months, 16 days ago) |
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tripsis: i would define evolution of the universe as being different from the evolution of organisms, although it's a neat comparison, i wonder if there's anything in it.
Aren't viruses living? My only source is wiki here, but it seems like there is a bit of a debate about whether or not viruses are living organisms. As a total newb in this debate, it seems to me that if something is replicating and evolving, then it is living. By this strict definition of living, i can't see how simply possessing cells is a necessary condition for being alive, what is your opinion?
I'm interested in this RNA... I'll look into it further. I won't bore you with more questions without doing a bit of research.. one particular sentence that jumps out is "Like DNA, most biologically active RNAs including tRNA, rRNA, snRNAs and other, non-coding, RNAs are...". I assume that this means that there are biologically INactive RNAs floating around... If tripsis is right and it can be formed through chemistry alone, that would be very cool.
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RIP
Bigger and bolder and rougher and tougher in other words sucka there is no other...
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tripsis
biophile-misanthropist-doofer
Registered: 04/13/08
Posts: 3,826
Loc: Gondwana
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Re: Proton radiation and Evolution [Re: undergrounder]
#8543633 - 06/20/08 08:42 AM (3 months, 16 days ago) |
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Virii aren't living because they don't fulfill the requirements of what is living. The characteristics of life are:
- organisation - cellular or molecular order
- energy utilisation/metabolism
- maintenance of an internal constancy/homeostasis
- reproduction, heredity, evolution
- sensitivity - the ability to sense and respond to their environment/stimuli
Virii can evolve and have a binary sense of their environment (either inside host or not). What defines them as non-living though is the fact that they have no metabolism and they cannot reproduce without hijacking the hosts cell. They are incapable of manufacturing proteins themselves, so without a host are inert.
Also RNA per se hasn't actually been formed through chemical reactions alone, but synthetic polynucleotides very similar to RNA have been. Some of these are capable of self-replication, sometimes imperfectly replicating too, thus over time "evolving".
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Since we depend on an abundance of functioning ecosystems to cleanse our water, enrich our soil and manufacture the very air we breathe, biodiversity is clearly not an inheritance to be discarded carelessly - Edward O. Wilson 1992
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johnm214
Registered: 05/31/07
Posts: 6,356
Loc: Americas
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Re: Proton radiation and Evolution [Re: zouden]
#8543746 - 06/20/08 09:28 AM (3 months, 16 days ago) |
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Quote:
zouden said: RNA has the ability to replicate itself even without any cellular machinery. So that's probably how the whole shindig got started.
Theoretic ability outside of living systems.
The ribozymes we know of no are pretty crappy from either a normal polymerase or practical point of view, and can't replicate so much as a gene. I believe the record is a turn or so of the helix, so that's certainly a limitation on the demonstrated ability of RNA to replicate itself without the normal stuff
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