Correct me if I am wrong, the idea is that a more complex system or a system with more ?parts? evolved and then lost ?parts? to reduce into IC? Is this a documented event as a whole or is this a speculation on how it could have happened?
Well in the particular context of IC it is hard to say if it has happened since there is no agreement upon exactly what constitutes an IC system or which systems are IC. If the question is if more complex systems can reduce then they certainly can, a prime example would be the numerous instances where independent parasitic organisms have lost their independence and become obligate parasites. If you mean is it documented as a whole as in have we actively observed every step of such a degradation in a laboratory then the answer is no, these things take a long time to occur. But neither is it mere speculation as there is compelling genetic evidence showing the derived nature of several obligate parasites from independent ancestors.
Has an IC system been shown to add information or adapt new parts?
Again without some clearly identified system agreed to be IC this is virtually impossible to answer and similarly without some functional definition of what constitutes genetic information this statement is impossible to address.
I think this idea begs the question of how much information must be added to supply a genome to reduce itself before a cell can be functional?
Once again the nature of the information you mean is unclear. Do you mean perhaps that there must be a minimum amount of genetic information, and specific information that performs a particular purpose, before a genome can
reproduce itself? There are a number of pre-cellular and pseudo cellular genetic systems which are possible and truly cellular life itself is usually considered a subsequent development. This is more an abiogenesis question than an IC question, unless the contention is that life itself is fundamentally IC. I may just have misunderstood the question.
As I understand it, information can only be added to the genotype one bit at a time and for every random positive mutation there must be consequentially a bit of information added most of the time.
I think that neither of these things is neccessarily true depending on your understanding of information. For the first point we can see entire genomes duplicate as one 'mutation'. While I agree that this deosn't neccessarily produce any novel information there are any number of informational metrics where such an event would represent a doubling in the informational content, and higher ploidy numbers are also commonly associated with increases in size, which may well represent a beneficial trait in some situations.
The second point, that a random positive mutation requires an increase in information, is definitely not true. In many cases it is beneficial for an organism to lose something it no longer needs, those reduced obligate parasites would be a prime example. In a permissive environment an organism that loses a feature which requires energy to produce or maintain but which is superfluous in its current environment has a beneficial increase in its available energy in that environment. Beneficial mutations need not represent an increase in genetic information.
Is this accurate or are there other ways to add information and please list if they are observed or hypothetical?
I can't tell if it is accurate or not, though I suspect not, or answer the rest of this query without a robust definiton of what you mean by genetic information. Spetner doesn't have to be lying, he might just be wrong.
He suggests that experiments have somewhat verified this postulate. I assume he is referring to his experiments in 1964. Is it possible that you are not aware of any such experiments or is he lying?
As far as I can tell the paper Spetner published in 1964 was in the 'Journal of Theoretical Biology', which as its name suggests focusses on theoretical speculations.
Because experiments have shown that most mutations are harmful, genes that already built up to be useful would suffer damage.
This is just plain wrong.
Most mutations are neutral. There is certainly a higher frequency of detrimental than beneficial ones though, as far as we have been able to determine. It is also worthwhile recalling that this is not occurring in individuals in isolation but in populations. While a particular gene may be compromised by mutation in an individual the original form will still be extant in the population. This is one reason why natural selection is considered such an important factor as it reduces the spread of such compromised alleles though the population, or in many cases they are so deleterious as to preclude their being passed on such as mutation which are lethal at the early stages of embryonic development.
Not all 'detrimental' mutations need be so lethal however and organisms could easily carry a substantial burden of such genes in a population provided the environment was not too severe. Without more information on how he gets to his conclusion whether this in anyway precludes evolution from fitting into current timeframes is hard to say.
I used transpose to mean basically change, I now understand I was potentially writing to geneticists. I apologize. I however, do not understand the use of the word "repredent," I could not find a definition anywhere I can only surmise what it means and I think it is an important adjective to unlocking your point.
The answer was right in front of you on your keyboard the d is right next to the s, unless you use Dvorak, it was simply a typo, my bad! The word should have been 'represent'.
However I hardly accept that any function or system in the genotype would "spring" into being fully formed. I accept that a Highly intelligent being created these systems as one would create a computer program for example.
What are you? A Raelian?
I would like your opinion. You are qualified enough to give a reasonable answer correct?
The chances of an individual getting some mutation are very high, almost every generation will introduce several mutations into a relatively large genome simply because copying during DNA synthesis while very good is not perfect. Most humans are though to have around 20-30 novel mutations, of some kind, compared to their parent. The chances of any particular mutation occurring are very small, although some are more likely than other, such as chromosomal abnormalities which crop up infrequently but with regularity.
Also, I would like to ask what is the chance of getting a positive mutation as opposed to a neutral and detrimental mutation?
Very low, but the chances of getting some positive mutation are higher and the chances of positive mutations persisting tends to be higher than either neutral or detrimental mutations although the degree varies dramatically depending on the specific case.
Are you suggesting that environmental context plays the majority role in natural selection? Does natural selection have any other methods of giving a higher selective value to a mutant organism?
depending on what one considers to constitute the environment I might be tempted to say it plays the whole role, if one were to allow the genetic environment of the cell and the other organisms in the individual's population to be considered environmental factors.
There are a myriad of factors which contribute to natural selection and as I suggest any one
could be considered environmental.
I think this is a good time to bring out the probability of survival in a mutant that has had a positive mutation. Assuming there is such a thing as a positive mutation as described by the Neo-Darwinian Theory.
I think it would be hard to dispute the existence of such mutations given the numerous experimental studies on factors such as antibiotic resistance in bacteria.
A mutant must have an above average offspring survival rate resulting in a higher selective value. The higher the selective value, the higher the chance that the mutant will survive to take over a population. Am I missing something?
Not anything particularly significant and Spetner's precis of Fisher is also correct, but do not forget that it applies equally to detrimental and neutral mutations.
There is more, however it seems that odds such as these very slim, and very slim to happen around the 500 times, that G. Ledyard Stebbins Processes of Organic Evolution 1966, predicted it would take to gain a new species.
I'm not familiar with the basis of Stebbins calculation but I don't think 500 could be taken as anything but a very approximate average even if it was reliable, as I pointed out before the genetic bases of reproductive isolation are highly variable. but even taking 500 as a fixed number then why is it of neccessity a problem, we would need to have both that figure and the calculated probability for mutations arising and being fixed to determine that. It also seems to assume that the contributing fixed mutations would necessarily be beneficial which need not be the case.
Spetner doesn't seem to put much stock in any other model of evolution other than copying errors to produce random mutations.
Well I might agree with this depending on what
exactly constitutes a copying error. If it just means point mutations then I would be less likely to agree. If it includes large scale gene duplications I would be happier.
He believes the other ways such as transposition fail to conclusively show their true randomness.
Well point mutations don't show 'true randomness' in the sense of all being equiprobable, the probability of a particular mutation is highly affected by the particular base involved the surrounding genetic sequence and the surrounding higher order structure of the chromosome.
So he rules out these early on, sticking to evolutions main pony - copying errors.
This would seem to limit the applicability of his conclusions right from the get go. It also make a potentially unwarranted assumption that the most frequent type of mutation, the single base substitution, is also the most important type of mutation.
Let's look at all of the ways evolution can produce random mutations in another thread, that I imagine would be an immense topic.
You got it back to front, it is the mutations that are one of the things that produce evolution. That might be an interesting thread, I tried to start a similar one before,
Mutation and its role in evolution: A beginners guide, but everyone thought it was too technical.
For now though, How many copying errors would it take to produce an active cumulative evolution?
I don't know that the phrase 'active cumulative evolution' makes any sense. As to how many 'copying errors' might be required I couldn't say offhand, especially since I'm not sure what you mean. I would tend to think it would be however many would have occured in a population in the time until two
de novo beneficial mutations, i.e new to the population, were both present in some individual, but it might just be the number until 2 mutations affecting the same trait occurred independently, as no further point mutations would be involved in the mutations being present together in some individual.
Also, how much information would need to be added with each corresponding mutation?
I certainly can't answer this question especially, as I already pointed out, since beneficial mutations can be caused by a loss of information, by most informational metrics.
I was under the impression that speciation as reproductive isolation was reversable and not subject to complete isolation in the genera or family. What is the stipulations for a complete speciation?
Reproductive isolation can be of several kinds, if it is the result of geographic isolation then it can often be reversed if the two populations are allowed to mix again. However given a long enough period of geographic isolation sufficient genetic changes, either influencing behaviour or directly affecting the biology of reproduction, may accrue that when reintroduced the two species cannot reintegrate. Some people use an even more stringent requirement that behavioural isolation is insufficient and that even in-vitro fertilisations should not produce fertile offspring.
I think the most common conception of speciation is that from the biological species concept, this includes geographical isolation as a suitable isolating factor except in flying species. I personally would ted to be a bit more stringent and want to see evidence of some reproductive isolation if the two potential species are reintegrated.
In this divergence has it been shown to increase the amount of information in the genome?
Again I can't answer this until you tell me how
you personally are measuring such information since there are several possible metrics.
Also, is the embryo the only known place these can occur outside of physical tampering?
Well the examples I am thinking of are cases where for one reason for another a particular gene fails to be expressed but a related gene compensates for its loss, this is sometimes even associated with an unusual spread of the expression domain of the second gene. This naturally principally occurs in embryos, although I imagine you might see similar effect in cell cultures, but I don't suppose that is what you meant. They may also persist into adulthood but that is a lot harder to study.
How scientific would it be to assume that this process can create the neccessary level of complexity we see in an IC system and even the amount of information prior to its subsequent devolution?
I don't see any particular barrier to it, but its hard to tell without proper deftions of several of the key terms, i.e. IC and information.
Are there any documented cases where a change causes a positive effect?
Certainly there are, including the very popular sickle cell related mutations. There are sickle cell types which both illustrate the highly context sensitive nature of the concept of beneficial, i.e.
Hbs providing an advantage to heterozygotes in areas where malaria is endemic, and ones which show that different mutations can perform the same function, the
Hbc allele which shows a much reduced severity of sickle cell symptoms although not in conjunction with
Hbs.
Is the smallest change restricted to a single nucleotide?
That is the smallest possible change.
How probable is this in a natural setting and how likely, by your best estimates, is this to occur in a natural setting? Your examples make me wonder how much "evolution" is to credit and how much adaptation resulting from prior information in the genome is to credit?
Well in the case of cancers many of the studies have been on tissues taken from 'nature' i.e. clinical samples an we can get a pretty good idea of the pre-cancerous genetic makeup based on the patients non-cancerous cells.
'Prior information' is obviously important as it is the raw material novel mutations work with. As we have both agreed new things are rarely likely to appear from nowhere. The closest to such a
deus ex machina would be examples where new proteins are thought to have originated from frame shift mutations, such as the nylon degrading protein
nylb see [thread=-9415].
I would very much like more information on this, I have read about resistences credited to evolution only to wonder how this would eventually effect the phenotype as we see in the phylogeny of our organisms.
I don't understand the issue. Are you wondering if the temporary benefits of resistance are outweighed by long term effects on the population? Evolution doesn't operate like that, if the resistant ones live and the non-resistant ones die then thats the important thing.
Are you saying we shouldn't be skeptical of unobserved phenomena that claims itself a scientific fact?
No I'm saying we shouldn't be skeptical of phenomena just because they haven't been directly observed when there is a huge body of directly observed evidence that supports their existence.
If I sequence the genomes of two identical twins then I should be able to infer that they are twins and therefore that they have the same parent, I don't have to have met the parents. Similarly patterns of similarity between organisms lead us to conclusions about their relatedness which don't rely on us having the genetic information of every preceeding generation inbetween from both lineages.
Evidences of processes that could have well been established by a designer and interpreted poorly by the design only gives me more of a reason to question what exactly is the evidence.
I hesitate to say it but the evidence is considerably greater than the evidence for there being any sort of creator. Why couldn't it be the ID camp that is poorly interpreting the design. Perhaps the designer just set up a minimal genome and let it go upon its own merry way through random mutation and natural selection, perhaps he made everyone and everything in a poof exactly as they are 5 minutes ago. Without knowing what sort of designer we are talking about or having any evidence for design its pretty much just empty speculation.
I hope you will continue in our discussion, I appreciate all the well mannered answers you have given.
You might be surprised what a lone voice yours is on that matter.
TTFN,
WK
Edited by Wounded King, : fixed link to nylon bug thread
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