by haujobbz 155 Replies latest jw friends
rem again:
The idea that humans decended from ancient fish-like creatures is a fact. The mechanism of how it happened is a theory. We call that theory "Evolution" and it contains several mechanisms, such as Natural Selection, Sexual Selection, Genetic Drift, etc.
rem
Edited by - hooberus on 29 October 2002 19:54:32
hooberus,
Virtually all creationist scientists accept micro-evolution as a verified phenomena.
If this is true, then what is the mechanism that Creation scientists believe keeps gene mutations from going beyond the species or the "kind" barrier? We know that mutations occur during replication (this is what drives micro-evolution, as you call it, unless you propose another mechanism)... there is no way to stop it and there is no known mechanism that keeps species or "kinds" defined. Mutations can and do add information, so evolution is not necessarily a lossy process.
In other words, what is to stop small changes from becoming large changes over time. A case in point is plate tectonics. Small changes over time accumulate form large "macro" formations (mountains and continents). This cannot be stopped without some type of mechanism.
rem
ps: I'm not sure why you are copying my posts. Care to explain?
Edited by - rem on 29 October 2002 20:8:2
rem I'm just trying to get your goat . . um er fish . by quoting your posts, no malice is intended.
One of the barriers prohibiting micro-evolution from being extrapolated into macro-evolution is that micro is an inforamation loosing process where large gene pools become smaller whereas macro is an information gaining process. You said that mutations can and do add information???? Please explain. do you have a couple of examples?
hooberus,
Sure, I can provide examples and scientific backing for my statement that mutations can and do add information. Mutations come in several forms. Note the bolded types below that add information:
http://www.talkorigins.org/faqs/mutations.html#types
Types of mutations:
- Point mutations
The most common type of copying error is the point mutation. In this form of mutation the nucleotide at a site is replaced by a different nucleotide. When people talk about mutation rates they are usually talking about rates of point mutations.
Effects of point mutations: Point mutations in junk DNA are common but have no effect. Sometimes point mutations in regulatory regions have no effect and sometimes they alter the expression of some genes.
- Additions and deletions
During copying a segment of DNA may be deleted or a new segment may be inserted. Typically this happens as a result of chromosome breakage or realignment. (See below.) Additions and deletions can also be produced by certain types of horizontal transfer.
Effects of additions and deletions: If the length of the new or deleted segment is not a multiple of three the translation will be garbled after the point at which the insertion/deletion occurred because the frame reading is now misaligned. This is known as a frameshift mutation. In some genes there are segments that may be duplicated as a block. This is known as tandem duplication.
- Chromosomal duplication
Sometimes one or more chromosomes are duplicated during reproduction; the offspring get extra copies of those chromosomes.
Effects of chromosomal duplication: Duplicating only one chromosome is generally disadvantageous; an example in human beings is Down's syndrome. Having multiple copies of all of the chromosomes is known as polyploidy. Polyploidy is rare in fungi and animals (although it does occur) and is common in plants. It has been estimated that 20-50% of all plant species arise as the result of polyploidy.
Gene duplication is very common; it is important because it provides a way to evolve new capabilities while retaining the old capabilities. All intermediate stages can be found in nature, from a single gene with alternate alleles to nearly identical duplicated genes with slightly different functional alleles to gene families of evolutionarily related genes with different functionalities.
- Chromosomal breakage and realignment
During reproduction a chromosome may break into two pieces or two chromosomes may be joined together. A section may be moved from one part of the chromosome to another or may be flipped in orientation (inverted). This is the mechanism by which deletions, duplications and transpositions my occur.
Effects of chromosomal breakage and realignment: Quite often these types of changes do not affect the viability of the organism (the genes are still there; they're just in different places) but, in sexually reproducing species, they may make it less likely for the organism to produce viable, fertile offspring.
- Retroviruses
Certain viruses have the ability to insert a copy of themselves into the genome of a host. The chemical that make this possible (reverse transcriptase) is widely used in genetic engineering.
Effects of retroviruses: Usually this is a way for the virus to get the host to do the work of reproducing the virus. Sometimes, however, the inserted gene mutates and becomes a permanent part of the host organism's genome. Depending on the position of the viral DNA in the host genome, genes may be disrupted or their expression altered. When insertions occur in the germline of multicellular organisms, they can be passed on vertically.
- Plasmids
Plasmids are little pieces of circular DNA that are passed from bacterium to bacterium. Plasmids can be transferred across species lines.
Effects of plasmid transfer: Plasmid transfer is an important way of spreading useful genes such as those which confer resistance to antibiotics. Plasmid transfer is an example of horizontal transfer.
- Bacterial DNA exchange
Bacteria can exchange DNA directly. They often do this in response to environmental stress.
Effects of bacterial DNA exchange: Exchange is often fatal to one or both of the bacteria involved. Sometimes, however, one or both of the partners acquires genes which are essential for the current environment.
- Higher level transfer
Some parasites can pick up genetic material from one organism and carry it to the next. This has been observed in fruit flies in the wild.
Effects of higher level transfer: When this happens novel alleles can spread much more rapidly through a species than they would for ordinary gene flow.
- Symbiotic transfer
When two organisms exist in a close symbiotic relationship one may "steal" genes from the other. The most notable example of this are mitochondria. In most organisms with mitochondria most of the original mitochondrial genes have moved from the mitochondria to the nuclear genome.
Effects of symbiotic transfer: A major effect is that the symbiotic relationship changes from being optional to be obligatory.
- Transposons
Transposons are genes that can move from one place in the genome to another.
Effects of transposons: Depending on the position of insertion, transposons can disrupt or alter the expression of host genes. In some species most mutations due to transposon insertion. For example, in Drosophila, 50-85% of mutations are due to transposon insertions.
Once a gene is duplicated here is how the extra information can be further mutated to add even more information:
http://www.talkorigins.org/origins/feedback/jun02.html
The February 2001 Post of the Month from the talk.origins newsgroup discusses information theory and the total hash that creationists make of it when analyzing evolution. Essentially, "information" in the colloquial sense that creationists use is not the same thing as "information" in information theory.
But even using the simplistic view of information that creationists use, it takes no effort to show that the "mutations can't add information" argument is utter hogwash. Consider a population of identical, asexually-reproducing organisms with the following genetic code:
ATTGTCAAGWe know that one possible mutation is for a section of the genome to be duplicated. So let's say that one of the organisms in the population has an offspring with a duplication mutation, like so:
ATTGTCAAGAAGAAGThis organism then reproduces. Its offspring has another mutation, one that substitutes several bases for their complements (T for A, C for G):
ATTGTCAAGATCTTGThat offspring reproduces. Now instead of one population of organisms with genome ATTGTCAAG, we have three:
- One with genome ATTGTCAAG.
- One with genome ATTGTCAAGAAGAAG.
- One with genome ATTGTCAAGATCTTG.
Even under the creationist idea of information, there is clearly "new information" from the first genome to the third. And it doesn't stop there; one could easily envision other duplications and point mutations such that the "final" genome looked nothing like the "original."
The creationist argument that "mutations can't add information" is simply wrong.
Here is more information about the flawed Creationist information theory:
http://www.talkorigins.org/origins/postmonth/feb01.html
and
http://www.talkorigins.org/faqs/fitness/
1.2.2 Information theory arguments While a detailed mathematical consideration of information theory is beyond the scope of this article, none of the creationist arguments based on information theory that I am aware of adequately address the obvious increase in information that can occur when a gene duplicates and the two copies undergo independent mutations leading to two genes with somewhat different functions. Gene duplication, mutation and selection are all known to occur due to natural biochemical processes in a variety of organisms studied in the laboratory. Many gene families are known with members that encode proteins having related structure and related but distinct function. Each family can be explained by multiple gene duplications followed by random mutation and differentiation of the functions of the individual gene copies. Clearly the expansion from a single primordial gene to a large family of genes with distinct functions represents an increase in genetic information. An example that I have already mentioned in another posting on Talk.Origins is the hemoglobin/myoglobin family. The gene for a primordial oxygen-carrying protein is thought to have duplicated leading to separate genes encoding myoglobin (the oxygen-carrying protein of muscle) and hemoglobin (the oxygen-carrying protein of red blood cells). Then the hemoglobin gene duplicated, and the copies differentiated into the forms known as alpha and beta. Later, both the alpha and beta hemoglobin genes duplicated several times producing a cluster of hemoglobin-alpha-related sequences and a cluster of hemoglobin-beta-related sequences. The clusters include functional genes that are slightly different, that are expressed at different times during the development of the embryo to the adult, and that encode proteins specifically adapted to those developmental periods. Other examples of gene families that appear to have developed by such duplication and differentiation include the immunoglobulin superfamily (comprising a large variety of cell surface proteins), the family of seven-membrane-spanning domain proteins (including receptors for light, odors, chemokines and neurotransmitters), the G-protein family (some members of which transduce the signals of the seven-membrane-spanning domain family proteins), the serine protease family (digestive and blood coagulation proteins) and the homeobox family (proteins critical in development). A large part of the increase in information in our genomes compared with those of "lower" organisms apparently results from such gene duplication followed by independent evolution and differentiation of duplicated copies into multiple genes with distinct function. If an information theory analysis claims that random mutation cannot lead to an increase in information but the analysis ignores gene duplication and differentiation through independent mutations, such an analysis is irrelevant as a model for gene evolution, regardless of its mathematical sophistication.
rem
Edited by - rem on 29 October 2002 21:3:26
well rem, you have posted quite a lot of material here. I'll try to do my best to give my observations although it might take some time. Your fist box discussing mutations is shown below:
Types of mutations:
- Point mutations
The most common type of copying error is the point mutation. In this form of mutation the nucleotide at a site is replaced by a different nucleotide. When people talk about mutation rates they are usually talking about rates of point mutations.
Effects of point mutations: Point mutations in junk DNA are common but have no effect. Sometimes point mutations in regulatory regions have no effect and sometimes they alter the expression of some genes.
- Additions and deletions
During copying a segment of DNA may be deleted or a new segment may be inserted. Typically this happens as a result of chromosome breakage or realignment. (See below.) Additions and deletions can also be produced by certain types of horizontal transfer.
Effects of additions and deletions: If the length of the new or deleted segment is not a multiple of three the translation will be garbled after the point at which the insertion/deletion occurred because the frame reading is now misaligned. This is known as a frameshift mutation. In some genes there are segments that may be duplicated as a block. This is known as tandem duplication.
- Chromosomal duplication
Sometimes one or more chromosomes are duplicated during reproduction; the offspring get extra copies of those chromosomes.
Effects of chromosomal duplication: Duplicating only one chromosome is generally disadvantageous; an example in human beings is Down's syndrome. Having multiple copies of all of the chromosomes is known as polyploidy. Polyploidy is rare in fungi and animals (although it does occur) and is common in plants. It has been estimated that 20-50% of all plant species arise as the result of polyploidy.
Gene duplication is very common; it is important because it provides a way to evolve new capabilities while retaining the old capabilities. All intermediate stages can be found in nature, from a single gene with alternate alleles to nearly identical duplicated genes with slightly different functional alleles to gene families of evolutionarily related genes with different functionalities.
- Chromosomal breakage and realignment
During reproduction a chromosome may break into two pieces or two chromosomes may be joined together. A section may be moved from one part of the chromosome to another or may be flipped in orientation (inverted). This is the mechanism by which deletions, duplications and transpositions my occur.
Effects of chromosomal breakage and realignment: Quite often these types of changes do not affect the viability of the organism (the genes are still there; they're just in different places) but, in sexually reproducing species, they may make it less likely for the organism to produce viable, fertile offspring.
- Retroviruses
Certain viruses have the ability to insert a copy of themselves into the genome of a host. The chemical that make this possible (reverse transcriptase) is widely used in genetic engineering.
Effects of retroviruses: Usually this is a way for the virus to get the host to do the work of reproducing the virus. Sometimes, however, the inserted gene mutates and becomes a permanent part of the host organism's genome. Depending on the position of the viral DNA in the host genome, genes may be disrupted or their expression altered. When insertions occur in the germline of multicellular organisms, they can be passed on vertically.
- Plasmids
Plasmids are little pieces of circular DNA that are passed from bacterium to bacterium. Plasmids can be transferred across species lines.
Effects of plasmid transfer: Plasmid transfer is an important way of spreading useful genes such as those which confer resistance to antibiotics. Plasmid transfer is an example of horizontal transfer.
- Bacterial DNA exchange
Bacteria can exchange DNA directly. They often do this in response to environmental stress.
Effects of bacterial DNA exchange: Exchange is often fatal to one or both of the bacteria involved. Sometimes, however, one or both of the partners acquires genes which are essential for the current environment.
- Higher level transfer
Some parasites can pick up genetic material from one organism and carry it to the next. This has been observed in fruit flies in the wild.
Effects of higher level transfer: When this happens novel alleles can spread much more rapidly through a species than they would for ordinary gene flow.
- Symbiotic transfer
When two organisms exist in a close symbiotic relationship one may "steal" genes from the other. The most notable example of this are mitochondria. In most organisms with mitochondria most of the original mitochondrial genes have moved from the mitochondria to the nuclear genome.
Effects of symbiotic transfer: A major effect is that the symbiotic relationship changes from being optional to be obligatory.
- Transposons
Transposons are genes that can move from one place in the genome to another.
Effects of transposons: Depending on the position of insertion, transposons can disrupt or alter the expression of host genes. In some species most mutations due to transposon insertion. For example, in Drosophila, 50-85% of mutations are due to transposon insertions.
My main comment here is that these types of mutations seem to be shuffling around and re-copying, exchanging, inserting, deleting, duplicating, passing around, transfering, and stealing ALREADY EXISTING genetic information. hense no new information is actually added.
hooberus,
If information is copied from one area and concatenated to another, then information most certainly has been added. Couple that with the fact that those new genes are now subject to mutation, the information can not only be added, but changed. DNA information is significant not only in it's content, but also in it's relative location on the genome. Also, with horizontal mutations new information is being introduced from different organisms. This is definitely new information to the host organism. If you read the cited articles it makes this clear.
rem
Edited by - rem on 29 October 2002 22:37:45
Your second box is shown below:
Once a gene is duplicated here is how the extra information can be further mutated to add even more information:
http://www.talkorigins.org/origins/feedback/jun02.html
The February 2001 Post of the Month from the talk.origins newsgroup discusses information theory and the total hash that creationists make of it when analyzing evolution. Essentially, "information" in the colloquial sense that creationists use is not the same thing as "information" in information theory.
But even using the simplistic view of information that creationists use, it takes no effort to show that the "mutations can't add information" argument is utter hogwash. Consider a population of identical, asexually-reproducing organisms with the following genetic code:
ATTGTCAAGWe know that one possible mutation is for a section of the genome to be duplicated. So let's say that one of the organisms in the population has an offspring with a duplication mutation, like so:
ATTGTCAAGAAGAAGThis organism then reproduces. Its offspring has another mutation, one that substitutes several bases for their complements (T for A, C for G):
ATTGTCAAGATCTTGThat offspring reproduces. Now instead of one population of organisms with genome ATTGTCAAG, we have three:
- One with genome ATTGTCAAG.
- One with genome ATTGTCAAGAAGAAG.
- One with genome ATTGTCAAGATCTTG.
Even under the creationist idea of information, there is clearly "new information" from the first genome to the third. And it doesn't stop there; one could easily envision other duplications and point mutations such that the "final" genome looked nothing like the "original."
The creationist argument that "mutations can't add information" is simply wrong.
My comment here for now is that while the initial genetic code of ATTGTCAAG was mutated into two other longer codes, this did not in itself add information. In order to add information you would not only have to lengthen the genetic sequence, but the added letters would have to be ARRANGED like the letters of the alphabet into functional "words."
I would also like to refer interested parties to an arcticle at :
http://www.trueorigin.org/schneider.asp
I am by no means an expert on information theory or genetics but these are my observations. I might have more in the future.
rem said:
"If information is copied from one area and concatenated to another, then information most certainly has been added. "
Well rem, while information has been added to the new area it still came from existing information from somewhere else. No one doubts that information can be taken from one area and moved to another, but this is different than assembling the info in the first place. For example we can cut and copy information from the talk-origin site and move it here thus increasing the amount of information on this site. However this does not explain how the information originally came into being.
In order to add information you would not only have to lengthen the genetic sequence, but the added letters would have to be ARRANGED like the letters of the alphabet into functional "words."
This is false. A lengthened genetic sequence automatically contains new information. The new information may be useless, garbled junk, but it is still new information. This new information, which may be useless at the moment, can be further modified by successive Point Mutations. Natural Selection will select beneficial mutations from the new information.
In summary:
First the selection of genetic information is duplicated, inserted, or concatenated somewhere in the sequence. Then that new area of information is subject to further mutation. The first act of inserting the genes already added information that was not in the gene sequence before. Further mutations and Natural Selection simply make the new information more beneficial for the organism. The brief article you and I quoted explains this process quite clearly.
rem
Hooberus,
Well rem, while information has been added to the new area it still came from existing information from somewhere else.
The place where the information originally came from is also subject to mutation, so the information could be completely foriegn, such as information from another organism (horizontal mutation). Remember, the coding is not the only thing that is important. It's location within the genome is also important. This is where you are going wrong - you are not understanding that even if the exact same sequence is copied to another area, that does not mean that it's the same information anymore. If the information is in a different area, then it performs a different function, thus new information.
Although I hate to do this, you can liken it to computer memory. Computer memory is all made up of 1's and 0's. Though there may be many places where the same sequence of 1's and 0's exist within the computer memory, they do different things based on the memory address. This is analogous to the location of the gene sequence on the gene. Hackers rely on this by inserting innocuous looking code into certain memory areas that act on that code. In one memory address, the computer code is benign... in another, it can gain priveleged access or other bad things.
I used to do this all of the time on my Commodore 64 when I was a little kid. I would "poke" certain data patterns into memory. If I looped the same pattern over and over again, the computer would do weird things (make noises and display weird graphics) because those data patterns meant something special in those memory locations. Note that all I was doing was copying a certain pattern, moving over a few memory address spaces and concatenating the same pattern.
Hope that helps,
rem
