Evolution or Creationism, Where does the evidence lead?

[paximperium]

One only has to read this to see that Garry has absolutely no rational retort to anything UnrepentantSinner has posted.

Not only are we descended from apes, we are still apes.

Yes...and your point?

We are living apes!

Yes we are. Your point?

So I did a little research on the vaunted fruit fly experiments to recall what I thought evolutionists have insisted was evolution in action and witnessed.

And? Did you have any opinion of the research?

In my search, I came across the neatest little machine called The Random Mutation Generator. (If you want to really see evolution in action, check it out. It is a real eye opener.)

In what way is it an eye opener?

That aside, I found an article that clearly contradicts what Steve has argued. An article titled "Fruit Fly Genetics" from guardian.co.uk insists that Theodosius Dobzhansky's experiments prove that new species through evolution has now been witnessed.
<snip>
Evolution in action! One living species becoming a different living species.

Yeah. What about it?

 

[politas]

In my search, I came across the neatest little machine called The Random Mutation Generator. (If you want to really see evolution in action, check it out. It is a real eye opener.) But that's off topic.

It isn't actually off-topic at all, apart from the fact that the Random Mutation Generator[/quote] is not in any way a reasonable simulation of evolution. It mimics a single organism replacing itself by non-sexual reproduction and dying in the process. With no population to operate on, it cannot simulate evolution, which, as has been mentioned, is a change in the frequency of heritable characteristics in populations of organisms over time.

As such, The Random Mutation Generator does not demonstrate evolution in action at all.

 

[UnrepentantSinner]

I'm sorry, but my Internet connection is giving me guff this morning, but I'm stubborn enough to try and address at least a few things before going to bed (Garry, I work nights.) Sorry for not providing links now, but I will tonight when I'm back at work.

I continually hear the argument that the 98% DNA similarity between chimps and humans absolutely proves that...

Actually no. First, science doesn't "absolutely prove" anything. Proof is the perview of math and alcohol, and colloquially in law. All science must allow for falsification. Just because apples always fall from a tree doesn't mean at some point they might flitter upwards. Second, there are multiple lines of genetic evidence that humans share a common ancestor with our fellow apes. Endogenous retroviruses, pseudogenes, and most tellingly the telomeres and centomeres on human chromosome 2. Thirdly, the fossil evidence seems to correlate with humans and chimps sharing a common ancestor - I not you didn't respond to the skull question I posted earlier. Finally, while some comparisons of the human and chimp genome have found differences as high as 5%, the active genes... that is those most responsible for making chimps chimps and humans humans have shown around a 99% match.

The totality of the genetic evidence, combined with the fossil evidence, including historical biogeography makes human/chimp common ancestry, not "absolutely proven" but virtually assured.

...like Mr. Sinner has so aptly stated above, "Myth #1- Men evolved from apes…Not a myth. Humans are apes that descended from an ape like common ancestor that we share with our fellow apes." Not only are we descended from apes, we are still apes.

I refer you to the Wiki and ToL links I posted above.

When I use Brian's quote "Nobody has ever suggested that one living species changes into a different living species", Mr. Sinner confirms that "That's half, and I bet inadvertently, correct. Populations, over time, build up mutations which, if not spread amonst the entire population, can result in subspeciation. Further, over longer periods of time, those new subspecies populations can lead to new taxonomic relationships between those subspecies." Again Mr. Sinner; "I pointed out where "humans evolved from apes" is a gross oversimplification above. Humans are part of the Hominoidea that includes all living apes (including us) and our extinct common ancestors and cousin species." We are living apes!

I don't mean to be rude, but you're talking in circles here. Brian's quote and my clarifications of it based on your misunderstaning are basically the same thing. And my offer to explain to you how species relate to taxonomy/the phylogenetic tree still stands.

So I did a little research on the vaunted fruit fly experiments.{snip}

How about before we get into fruit fly experiments (did you take my link on HOX genes and how they effect body development and how they are present in beings as different as flies, fish and wombats?), how about we stick with hominid evolution for now and you address speciation within evolutionary theory or creationism? This topic is not a Rohrsach test where you can see and describe whatever you want at any given moment. There are specifics that must be addressed before we can move on to other topics.

I said it earlier tonight. I've given you plenty of stuff in response to issues you have raised for you to respond to. How about you respond to it before moving on to other topics?

 

[smloeffelholz]

I continually hear the argument that the 98% DNA similarity between chimps and humans absolutely proves that, like Mr. Sinner has so aptly stated above, "Myth #1- Men evolved from apes…Not a myth. Humans are apes that descended from an ape like common ancestor that we share with our fellow apes." Not only are we descended from apes, we are still apes.

Again, the myth listed on the site is that men evolved from modern apes. The word modern makes a world of difference in that sentence. The idea that man evolved from an ancient species of ape that is now extinct (ie shares a recent common ancestor with modern great apes) has long been a part of evolutionary theory. The idea that man evolved from either chimps or gorillas that you can visit in a zoo is a myth, in that the only people who believe that evolution supports this claim are people misinformed about evolution or creationists.

That aside, I found an article that clearly contradicts what Steve has argued. An article titled "Fruit Fly Genetics" from guardian.co.uk insists that Theodosius Dobzhansky's experiments prove that new species through evolution has now been witnessed.

I read the entire article, and it doesn't contradict anything that I said in my previous post. I said, "I believe that the point he was trying to make is that no organism, in its own lifetime, will change into a different organism, or that no organism will ever produce progeny completely unlike itself (ie a rat never gave birth to a bat)." Where does the article contradict this statement, or any other statement that I made?

 

[Garry Webb]

Trinitarian Troll

Sinner Man, I studied an article on HOX genes and found some very interesting facts; although I am not sure they are what you had in mind.

Firstly, the many similar building blocks of carbon based lifeforms is what should be expected in a common creation. No new news there.

This statement is very enlightening though: “Homeotic genes set up the basic regional layout of an organism, so that eyes form on the head and not on the abdomen, and limbs form at the sides and not on the head. Even a single mutation in the DNA of these genes can have drastic effects on the organism (see Homeotic Mutants, below), and so these genes have changed relatively little over time.” What does that mean; “these genes have changed relatively little over time”? And what happens when they do change?

The “see Homeotic Mutants, below” section, redirected me to where the answer to that question was.That very question was answered by Edward B. Lewis in 1995, winning him the Nobel Peace Prize. The story of his research can be found on the nobelprize.org website and it details his discoveries. Alongside a picture of the fly research is this caption: “A normal adult fruit fly, enlarged 40 times. To the right the fly's ill-fated cousin, a mutant with 4 wings but no balance organs. This now famous little "monster" was a starting point for Lewis in his research on homeotic transformations. Lewis found that the extra pair of wings was due to a duplication of an entire body segment, the 2nd thoracic segment. Inactivity of the first gene of the bithorax-complex in the appropriate larval segment caused other homeotic genes to respecify the 3rd thoracic segment into one that forms wings instead of halteres.” In other words, “mutation almost always very bad!”

Is this one of your evidences of evolution?

In closing, I have some young students that are curious as to what is up with you guys repeating every sentence that I post? Are you trying to avoid the actual issues that have been raised, and…..”what is the point?”

 

[Garry Webb]

Trinitarian Troll

Steve, I understand the problem that you face in now trying to disassociate your ideology with what I say that evolutionists must believe. In order for Darwinian evolution to be true, every organism that is capable of passing on inheritable traits to successive generations must, within its own genetic coding, evolve the genetic information which it then passes on. The general definition of speciation as that which occurs when members of a species mutate to the point where they are no longer able to breed with other members of the same species. The new population becomes a reproductively isolated community that is unable to breed with its former community. Through speciation, the genes of the new population become isolated from the previous group.

The article of Fruit Fly Genetics from guardian.co.uk affirms that this is what Dobzhansky observed with his own eyes. If they did not change, why were they not able to mate with their own species? Twist it any way you can, but this is the basis for Darwinian evolution. An example of this belief is listed as Sympatric speciation which refers to the formation of two or more descendant species from a single ancestral species all occupying the same geographic location. How do non-existent species inhabit the same geographic location?

UrS proposes that we are apes not me. He’s the evolutionist; he should know!

 

[RecoveringYuppy]

In closing, I have some young students that are curious as to what is up with you guys repeating every sentence that I post? Are you trying to avoid the actual issues that have been raised, and…..”what is the point?”

It's so that people reading the conversation can tell what point from earlier in the conversation is being addressed.

Steve, I understand the problem that you face in now trying to disassociate your ideology with what I say that evolutionists must believe.

Here's a spot where you should quote because it's hard to tell who Steve is in this conversation. It also indicates you should refrain from telling other what they must believe.

In order for Darwinian evolution to be true, every organism that is capable of passing on inheritable traits to successive generations must, within its own genetic coding, evolve the genetic information which it then passes on.

No. For Darwinian evolution there has to be descent with modification. Actual mechanism wasn't specified. However we now know that what you describe is wrong. Modification happens at reproduction amongst sexually reproducing life forms.

UrS proposes that we are apes not me. He’s the evolutionist; he should know!

Yes, apes. Not modern apes.

 

[smloeffelholz]

This now famous little "monster" was a starting point for Lewis in his research on homeotic transformations. Lewis found that the extra pair of wings was due to a duplication of an entire body segment, the 2nd thoracic segment. Inactivity of the first gene of the bithorax-complex in the appropriate larval segment caused other homeotic genes to respecify the 3rd thoracic segment into one that forms wings instead of halteres.” In other words, “mutation almost always very bad!”

I would have to say that your last statement is not true. Many mutations are silent, and cause no change in a protein whatsoever. A mutation that changed a CUU codon into a CUA codon would not change the protein at all. A leucine amino acid would still be correctly placed in the protein and it would function normally. Further, if the mutation switched one non-polar amino acid for another similarly sized non-polar amino acid, there is a good chance that the protein, though slightly altered, would still function normally. When the mutation does significantly change the protein (by causing a frame shift, premature stop codon, or replacing an amino acid critical for correct folding and therefore function), it is true that usually this change is not beneficial. But since it is usually not beneficial, that means that some are beneficial and can increase the fitness of the organism. For an example of one such beneficial mutation, look into the CCR-5 gene and its link to HIV immunity. A person with this mutation is seemingly unaffected except that they are immune to HIV infection.

In order for Darwinian evolution to be true, every organism that is capable of passing on inheritable traits to successive generations must, within its own genetic coding, evolve the genetic information which it then passes on.

This is also not true. If I understand correctly (and someone please correct me if I am wrong), the random mutations that drive the process of evolution are almost exclusively produced during the process of meiosis and appear in the gametes. A mutation within a somatic cell (the cells with the genetic coding for the organism itself) does not have the potential to spread throughout an entire organism. This means that the mutation will not be passed on to future generations. A mutation in a gamete (the cells that carry the genetic information for the organisms potential offspring) will automatically be present in every cell of the offspring.

The general definition of speciation is ...[snip]

The article of Fruit Fly Genetics from guardian.co.uk affirms that this is what Dobzhansky observed with his own eyes. If they did not change, why were they not able to mate with their own species?

Once again your paraphrasing is completely inaccurate. The article says, "In accumulating genetic differences, Dobzhansky saw how two populations might also accumulate differences in body size, colour, genital architecture, behavioural idiosyncrasies, and a thousand other characteristics that could eventually make them reluctant or unable to mate with one another. In these distinct genetic profiles, Dobzhansky believed he was seeing the origin of species in its infancy."

In other words, he witnessed how quickly genetic changes could occur in the fruit fly population and realized that these changes could accumulate over time in two different populations until one population became reproductively isolated from the other. It does not say that he witnessed the origin of a new species. Instead, it says he hypothesized that he was watching the very beginning of the process and saw how it could eventually lead to a speciation event. The article also doesn't say that he witnessed two populations become reproductively isolate without changing. It just says that he saw how genetic differences, accumulated over time, could lead to problematic mating between the two populations. Neither of these observations is contrary to current evolutionary theory. Perhaps you should read more carefully, and try to put aside your biases when interpreting literature.

Finally, I have to agree with UrS that you are jumping all over the place. Once someone brings up several points to counter one of your arguments, you switch topics without ever addressing their points. Are we to assume that you are admitting to your argument being flawed, or is there another reason for your sporadic topic choices?

 

[Garry Webb]

The Trinitarian Troll

Steve, in your last post, on the topic of beneficial mutations, you offered this statement: “For an example of one such beneficial mutation, look into the CCR-5 gene and its link to HIV immunity. A person with this mutation is seemingly unaffected except that they are immune to HIV infection”, actually, people with this mutation, including AIDS patients that may be treated with Chemokine Receptor 5 (CCR5) inhibitors, are in fact susceptible to several very serious maladies including encephalitis, West Nile Virus, schizophrenia, meningitis, and aseptic meningoencephalitis.

In a study documented @ www .liu.se /content /1/c6/11/88/57/2008/Malin_Eriksson.pdf entitled “Potential Risks Associated with the Introduction of CCR5 Antagonists as HIV-1Treatment” it is also been found that both the natural mutation and therapy treatments may actually cause longer reaching adverse affects including drug resistance. Apparently, the mutation can provide measured resistance to the AIDS virus, but one researcher warned that “Unfortunately, there are serious side effects to the treatment and viral resistance is an increasing problem.” Humans do not even synthesise amino acids such as Leucines, which contain the CUU and CUA codons. Please explain this inference of molecular evolution, as I do not get this connection.

Since you have invited us to correct you if you are wrong, when you infer that “…the random mutations that drive the process of evolution are almost exclusively produced during the process of meiosis and appear in the gametes”, where do the Gametes get their genetic information? If I am not mistaken, before meiosis begins, the DNA in the original cell is replicated. Unless there is a mutation of sorts, the information is copied. It does not just make something up.

Also, meiosis does not occur in bacteria and other prokaryotes. If I am not mistaken, you do believe that these organisms have evolved do you not?

 

[RecoveringYuppy]

Humans do not even synthesise amino acids such as Leucines, which contain the CUU and CUA codons. Please explain this inference of molecular evolution, as I do not get this connection.

He was giving an example of a mutation which has no effect.

You seem a bit confused in the quote above. No, leucine is not sunthesized by humans, it is used by humans in protein building. Proteins do not contains codons at all. Codons are the code in the DNA that specify an amino acid.

 

[RecoveringYuppy]

Since you have invited us to correct you if you are wrong, when you infer that “…the random mutations that drive the process of evolution are almost exclusively produced during the process of meiosis and appear in the gametes”, where do the Gametes get their genetic information? If I am not mistaken, before meiosis begins, the DNA in the original cell is replicated. Unless there is a mutation of sorts, the information is copied. It does not just make something up.

What exactly do you think was wrong in the post you are replying to?

Yes, gametes get their original DNA from their host. They copy half of it and there are usually mutations (which is "making something up) during the copying. This is the source of variation that drives evolution.

 

[UnrepentantSinner]

In closing, I have some young students that are curious as to what is up with you guys repeating every sentence that I post? Are you trying to avoid the actual issues that have been raised, and…..”what is the point?”

It's a courtesy I picked up when I first started using the web so the person I'm responding to knows exactly what I'm responding to. I'd note that paximperium chose selected sentences and that I {snipped} a few portions of your post this morning.

Speaking of responding, I'll get to what was posted today while I slept as down time at work permits.

 

[smloeffelholz]

...actually, people with this mutation, including AIDS patients that may be treated with Chemokine Receptor 5 (CCR5) inhibitors, are in fact susceptible to several very serious maladies including encephalitis, West Nile Virus, schizophrenia, meningitis, and aseptic meningoencephalitis.

When you make comments like this, are you just hoping that no one is going to check your sources? First, everyone is susceptible to these diseases. What the paper says is that, "...results suggest that the deletion causes an increased risk for symptomatic West Nile virus infection, symptomatic tick-borne encephalitis and late-onset schizophrenia..." This means that some research (which I have not yet been able to find) suggests that this mutation could cause a higher chance of contracting one of these rare diseases. On top of being very rare (the ones I could find had incidence rates around 10k per 150 mil annually), your description of these diseases as very serious is misleading considering that their mortality rates are around 1-2%. When these cons are weighed against the benefit of being immune to a disease with a 100% mortality rate and higher incidence, it is still safe to say that this is a beneficial mutation.

Humans do not even synthesise amino acids such as Leucines, which contain the CUU and CUA codons. Please explain this inference of molecular evolution, as I do not get this connection.

I am not saying this as an insult, but this statement highlights your lack of general science understanding. Although it is true that humans cannot synthesize the amino acid leucine (it is an essential amino acid and must be ingested), this molecule is commonly found in human proteins. Leucine itself does not contain codons. The mRNA that codes for protein synthesis is made up of codons, some of which code for the amino acid leucine. I was making the point that not only are the vast majority of mutations not harmful, but that many of them are silent and cause no change whatsoever. To better understand how amino acids, proteins, DNA, mRNA, and codons are related, you should look into the processes of transcription and translation.

Since you have invited us to correct you if you are wrong, when you infer that “…the random mutations that drive the process of evolution are almost exclusively produced during the process of meiosis and appear in the gametes”, where do the Gametes get their genetic information? If I am not mistaken, before meiosis begins, the DNA in the original cell is replicated. Unless there is a mutation of sorts, the information is copied. It does not just make something up.

If you read what you wrote, you prove my point. The DNA for meiosis comes from the parent organism. When this DNA is copied to start the process of meiosis, occasionally mistakes are made called mutations. Mutations can also occur through other means, such as mistakes that can happen during crossover events. These mutations can be passed on to the progeny, even though these mutations were never present in the parent organism. This is scientific fact and directly disputes your comment, "...every organism that is capable of passing on inheritable traits to successive generations must, within its own genetic coding, evolve the genetic information which it then passes on."

Also, meiosis does not occur in bacteria and other prokaryotes. If I am not mistaken, you do believe that these organisms have evolved do you not?

I apologize because I was not specific enough when I made my earlier comment about where random mutations occur. I was referring to sexually reproducing organisms, and I am sorry if this caused any confusion. Still, your logic does not hold up even in the world of bacteria and prokaryotes. When a bacteria reproduces asexually, it must duplicate its entire genome. This second copy of the genome then migrates away from the original copy of the genome, and the cell splits in two. This usually creates an identical organism, but occasionally a mistake is made when the genome is being duplicated, and this mutation is passed on to the daughter cell while not affecting the parent cell. Once again, the parent cell does not need that mutation to be present for it to occur in the daughter cell. This allows for these organisms to evolve, and recently some excellent examples of bacteria evolution have been demonstrated.

 

[UnrepentantSinner]

I hate to do this, but in response to your question about using quote tags, I have to ask what's up with repeatedly using the Trinitarian Troll post title? We really don't need them to keep track of who is responding to whom here and it just adds fuel to the fire that has me thinking you want to argue against atheism, not the science supporting Creationism or evolution.

Just to be clear, I'm only interested in arguing the science behind Creationism and evolution.

Also I'm sorry that I didn't provide links for the pseudogene, ERV and human chomosome 2 comments I made above and I'm not going to be able to until late Tue. night. I was busy at work and with the daylight savings time simply didn't have the time. I'll be at home on dial-up for the next two days so any responses I made over that time will have to be sans links. The evidence is out there and if no one else covers for me, I'll make sure and provide it for you when time and bandwidth allows.

Sinner Man, I studied an article on HOX genes and found some very interesting facts; although I am not sure they are what you had in mind.

Firstly, the many similar building blocks of carbon based lifeforms is what should be expected in a common creation. No new news there.

Two incorrect assertions. First, you're right that that it would be expected that carbon based life would all have, axiomatically, life based on carbon. But that's not what the HOX genes represent. They are genes, made of protiens and that's much more of an evidence than merely having the same components. I mean rust has iron in it and blood has iron in it, but you're not going to suggest life is the same as a sunken ship are you?

Second, you're incorrect by using the phrase "common creation". There is utterly no reason for a fiat creation to exhibit the same genes being used in insects, fish and humans to create body sections or appendages. A fiat creator could use any genes or any combination of protiens or, well, anything to create, well anything. Starfish could use silica to create their skins, Placoderms could have used cobalt to armor their heads, mammals could have used fructose in their milk instead of lactose.

The phrase you were looking for was "common design" and we don't see that either. Cephalapods have complex eyes like tetrapods do, but they're inverted. Humans have the same number of vertebra as giraffes, but they don't appear to have back problems like we do. Some mammals can digest plants with great efficiency (over the course of time in their guts) and some can only eat meat. Terrestrail tetrapods can choke on their food because the top end of our digestive system is merely a modification of what it was when our ancestors were fish. If one wants to make the "common design" argument, one is talking about a tinkerer or an incompitant.

This statement is very enlightening though: “Homeotic genes set up the basic regional layout of an organism, so that eyes form on the head and not on the abdomen, and limbs form at the sides and not on the head. Even a single mutation in the DNA of these genes can have drastic effects on the organism (see Homeotic Mutants, below), and so these genes have changed relatively little over time.” What does that mean; “these genes have changed relatively little over time”? And what happens when they do change?

What it means is that they are highly preserved. Some genes don't mutate for a very long time and then their areas can exhibit huge amounts of mutation in a geologically short amount of time. One example would be the HAR1 genes which effect brain devolopment. Most of the genes in that region (Human Accellerated Region 1) were preserved for 300+ million years. Then, about 7 million years ago there was a lot of mutations that stuck. That's just how mutation works.

Another part of preservation is that certain genes have been locked as master body planners over time. HOX genes are clearly ancient while genes that effect the expression of body parts has changed over time resulting in such divergency as salamanders, whales, birds, cats and dogs, lizards and humans.

The “see Homeotic Mutants, below” section,{snip} ...In other words, “mutation almost always very bad!”

Is this one of your evidences of evolution?

I'm snipping this so I can ask you a question via sports analogy. If we know, after studying hundreds of baseball players that a handful will hit well above average, the majority will hit within the range of average and another handful will hit poorly... is it honest on your part to focus on the handful that hit poorly while ignoring the vast majority that hit average and the handful that hit above average?

That said, see my comment above about how body plans don't manifest willy nilly, but are observably the result of common ancestry. That alone makes it an evidence for evolutionary theory.

 

[UnrepentantSinner]

Steve, I understand the problem that you face in now trying to disassociate your ideology with what I say that evolutionists must believe.

Everything Steve has said so far in this thread is correct. Perhaps not correct within your straw man and distorted understanding of evolutionary theory, but correct none the less. And this is just me talking but, wouldn't it be better for you to try to grasp what science advocates accept than insisting you know what they "believe" (see I can use scare quotes too)?

In order for Darwinian evolution to be true, every organism that is capable of passing on inheritable traits to successive generations must, within its own genetic coding, evolve the genetic information which it then passes on.

Kind of. To phrase it more economically, "organisms that reproduce pass on their genes to their offspring". That's Mendel 101 and Darwin 101 summed up in less than you find in most sylliby.

The general definition of speciation as that which occurs when members of a species mutate to the point where they are no longer able to breed with other members of the same species. The new population becomes a reproductively isolated community that is unable to breed with its former community. Through speciation, the genes of the new population become isolated from the previous group.

I think you've got it. Would this be an appropriate place for me to offer up my lesson on speciation, taxons and phylogenetic trees?

The article of Fruit Fly Genetics from guardian.co.uk affirms that this is what Dobzhansky observed with his own eyes. If they did not change, why were they not able to mate with their own species? Twist it any way you can, but this is the basis for Darwinian evolution. An example of this belief is listed as Sympatric speciation which refers to the formation of two or more descendant species from a single ancestral species all occupying the same geographic location. How do non-existent species inhabit the same geographic location?

Sexual selection for one. Some species of insects that would otherwise be interfertile won't mate because the songs of one species don't attract mates of the other species.

And don't discount the impact of geography. Ring species are a great example. There are tern species that circle the globe which are interfertile but if you took those at the "ends" of the geographic ranges they are not. The same is true of salamanders in California where every species is interfertile with the one next to it, but those on the "ends" while geographically proximate, are not.

UrS proposes that we are apes not me. He’s the evolutionist; he should know!

Sigh... I'm hoping Steve, et. al. will at least get this joke.

Humans are apes in that we are Hominidae in the same way we are fish in that we are Sarcopterygii.

 

[Garry Webb]

Just a few quick responses in the order of the posts since my last one. Got church tonight!

“Proteins do not contains codons at all.” Really? How then are they coded? The sequence by which they are structured is a codon. Specifically, Leucine codons are UUA, UUG, CUU, CUC, CUA, and CUG. What do you mean no codons? And it all depends upon whether the coding is canonical or simple genetic code, as the canonical genetic code is not universal. There is clear prolixity but no equivocation; thus the substitutions.

Steve, your original statement was “For an example of one such beneficial mutation, look into the CCR-5 gene and its link to HIV immunity. A person with this mutation is seemingly unaffected except that they are immune to HIV infection.” I was attempting to show that though appearing to be “seemingly unaffected” there are probable affects elsewhere. As with sickle cell and the malarial virus! The host is actually so ill from sickle cell that malaria cannot survive. Would you rather have sickle cell or malaria? I am not sure that intentionally causing the mutation is the answer to the AIDS problem, which is what the study discussed. Besides, HIV could be wiped off the face of the earth is humans would simply change their lifestyles; i.e. intravenous drug use and unprotected sex.

Biological evolution is commonly defined as change in the inherited traits of a population of organisms from one generation to the next. The three main processes causing changes are variation, reproduction, and natural selection or any combination of the three. By far, mutations are passed on hereditarily, and then, those caused by environmental means are far more random and deleterious.

In Darwinian evolution, natural selection is thought to cause many more heritable traits that are beneficial for survival and reproduction and would then cause harmful traits to become rarer; whereas, in genetic drift, produces random changes in the frequency of traits in any given population. It is defined as a result of the role probability plays in whether a given trait will be passed on as individuals survive and reproduce. Changes produced in any one generation by drift and beneficial selections are thought to be much smaller. These differences are believed to add up following each new generation and be the cause of enough changes in the organisms, even to the production and emergence of new species.

If heredity is the main vehicle by which mutations are successfully passed on, then it is rational to consider that each previous generation had indeed, evolved genetically.

 

[RecoveringYuppy]

“Proteins do not contains codons at all.” Really? How then are they coded?The sequence by which they are structured is a codon. Specifically, Leucine codons are UUA, UUG, CUU, CUC, CUA, and CUG. What do you mean no codons?

Codons are contained in the DNA and RNA sequences which describe the proteins, not in the proteins.

Steve, your original statement was “For an example of one such beneficial mutation, look into the CCR-5 gene and its link to HIV immunity. A person with this mutation is seemingly unaffected except that they are immune to HIV infection.” I was attempting to show that though appearing to be “seemingly unaffected” there are probable affects elsewhere. As with sickle cell and the malarial virus! The host is actually so ill from sickle cell that malaria cannot survive. Would you rather have sickle cell or malaria?

Doesn't matter which you'd rather have. It's the overall survival rate of the species that determines if a mutation is beneficial or not. If a traits benefits outweigh it's drawbacks it's still benefical. And "benefit" is measured species wide in nature.

 

[TX50]

[...] DNA is composed of 4 amino acids which are, basically, the letters that compose the language of life [...]

[...]They are genes, made of protiens [...]

I think you need to brush up on your biochemistry a bit. DNA is
not "composed of 4 amino acids", nor are genes "made of proteins".

 

[smloeffelholz]

“Proteins do not contains codons at all.” Really? How then are they coded? The sequence by which they are structured is a codon. Specifically, Leucine codons are UUA, UUG, CUU, CUC, CUA, and CUG. What do you mean no codons? And it all depends upon whether the coding is canonical or simple genetic code, as the canonical genetic code is not universal. There is clear prolixity but no equivocation; thus the substitutions.

No, no, no. Since you didn't take my advice and look into transcription and translation, I guess I will have to give you a whirlwind tour through the process. Proteins are large molecules made up of smaller subunits called amino acids. Amino acids are molecules consisting of an amine group, a carboxyl group, and a side chain that differs in each of the different amino acids. Certain parts of the DNA called genes contain a code that instructs the cell on how to make a certain protein. When that protein is needed, a single stranded copy of the gene is made that is called mRNA (transcription). On the mRNA strand, each three nucleotide sequence (beginning after the first AUG sequence) is called a codon. These codons each code for the addition of a specific amino acid. A cellular organelle called a ribosome reads this code and assembles amino acids in order to produce the protein coded for on the mRNA (translation). Proteins do not contain codons, the mRNA does. The codons that you listed above instruct the ribosome to add a leucine amino acid to the protein under construction. Therefore a mutation that changes one of those codons, into another one of those codons (ie CUU -> CUA) would be a mutation in the genetic code that is not harmful, and is completely silent.

I was attempting to show that though appearing to be “seemingly unaffected” there are probable affects elsewhere.

And I was pointing out that the affects elsewhere are extremely minor compared to the advantages of the mutation. This was to show that the mutation is beneficial even though there are some very minor side effects.

As with sickle cell and the malarial virus! The host is actually so ill from sickle cell that malaria cannot survive. Would you rather have sickle cell or malaria?

This is a perfect example of the logical fallacy of the excluded middle. You are claiming that you are either extremely sick and immune to malaria or perfectly healthy and susceptible to malaria when that is not the case. It is possible to have a single sickle cell mutation (instead of a mutation on both chromosomes). This type of mutation grants you limited resistance to malaria while avoiding many of the harmful and painful effects of full blown sickle cell anemia. In an area of the world where the threat from malaria is considerably large (such as parts of Africa), this mutation can confer a net benefit for a population even when factoring in those who end up with sickle cell anemia. In parts of the world where the risk of malaria is much lower (Europe and America), the disadvantages of the mutation outweigh the advantages and it is selected against. This is why we see such a high prevalence of the sickle cell mutation in African Americans while European Americans have a much much lower prevalence. Depending on the environment, the factor that drives natural selection, mutations can be selected for or against.

I am not sure that intentionally causing the mutation is the answer to the AIDS problem, which is what the study discussed.

Intentionally causing the mutation would be a form of gene therapy and that is not what was discussed in the paper you linked to. They were discussing using a CCR-5 antagonist (a molecule that would effectively block the activity of the CCR-5 protein, thus not allowing the HIV virus to use this protein to gain entrance to the cell). This treatment should be reversible (if you stopped taking the antagonist, your body could once again synthesize viable CCR-5) so the exact risk of the diseases mentioned in the paper need to be studied carefully. If they find that they have a 50% chance to halt the progression of HIV and only a 2% chance of contracting one of these diseases, then the treatment would be worth the risk. If they find that a 10% chance to halt the progression of HIV comes at the cost of a 20% chance of contracting these diseases, then the benefit is too low to justify the risk. Though more study is needed before these drugs are prescribed to the public, the idea should not be written off just because of some possible side effects.

In Darwinian evolution, natural selection is thought to cause many more heritable traits that are beneficial for survival and reproduction and would then cause harmful traits to become rarer; whereas, in genetic drift, produces random changes in the frequency of traits in any given population... (snip)

Natural selection does not cause mutations or beneficial traits. Natural selection can only select the most beneficial genes that already exist in the population. This selection is driven by the fitness of the organisms (survivability, reproduction rate, etc) which is dependent on the environmental conditions the organism exists in. This may seem like a nit-picky point, but it is very important to understand this. New mutations and gene variations are produced by random processes and duplication errors. Natural selection is the process that determines if the mutations and gene variations are beneficial or harmful depending on the environment that they exist in.

If heredity is the main vehicle by which mutations are successfully passed on, then it is rational to consider that each previous generation had indeed, evolved genetically.

I am not sure what you are trying to say here. Heredity is how beneficial mutations are passed on, but those beneficial mutations had to manifest at some point. In other words, at some point an organisms progeny had to have a beneficial mutation not present in the parent generation.

 

[UnrepentantSinner]

I think you need to brush up on your biochemistry a bit. DNA is
not "composed of 4 amino acids", nor are genes "made of proteins".

Ugh. Incorrect and poorly stated on my part. Thank you for reminding me to do a bit of a refresher before I write things like that.