Orphan genes -- open reading frames with no detectable similarity to any other known sequence -- constitute a surprisingly high percentage of the genomes of fully-sequenced organisms.
There are two claims here: 1) ORFans have no similarity to other sequences and 2) Common descent assumes all (or a very high proportion) of current proteins all originated with the LUCA. Claim 1 is deeply misleading and claim 2 is wrong. We fully expect a reasonable proportion of new genes to be generated de novo during evolution. We even have examples of proteins that are so generated. The most famous of these is the nylonase gene, which allows bacteria to metabolise the artificial polymer nylon. This was produced by a mutation in a piece of non-coding "Junk DNA" which generated a transcribable protein (Okada et al, 1983). The sperm-specific dynein intermediate chain gene was generated by a fusion mutation between two genes (so strictly speaking it falls under the gene duplication rubric), but the coding region of the new Sdic gene is generated from the non-coding intronic regions, so protein homology studies would have a hard time identifying it (Nurminsky et al 1998). Formation of new genes poses no problem for evolutionary biology or common descent. Lets look at claim 1 in more detail. Nelson gives the impression that these are all single genes with no relation to any other genes. In fact many ORFans actually come in families, and many genes with no apparent relationship to other genes at the time of discovery have often had relatives found after a while. In my own signal transduction field, a coding sequence originally thought to be an ORFan was finally identified as being opioid-receptor like, and its ligand found (called ironically Orphainin), and is now a drug target for analgesics. There are many instances where ORFans have been found to be related to extant genes. When H. influenzae was first sequenced, 64% of its ORF's were ORFans, now, only 5.2% are. There are of course things called singleton ORFans. Unique genes that do not currently seem to be related to existing genes per se. In prokaryotes, something like 14% of all bacterial genes are currently singleton ORFans, but this may be expected to decrease as we sequence more genomes (as with H. influenzae). Also we may be missing some related proteins, as ORFans may have diverged so much during evolution we can't currently identify their nearest relatives. Improved detection algorithms, against a background of improved gene databases, will reduce the number of ORFans. I'll remind you again that as well as these singleton ORFans, there are ORFans that are limited to closely related organisms, and ORFans that are found in families of organisms (just as if they were related by *gasp* common descent). Lets look at Nelsons treatment of this in a little more detail. He quotes Siew N, Fischer D (Twenty thousand ORFan microbial protein families for the biologist? Structure. 2003 Jan;11(1):7-9) a three page mini-Review.According to the Theory of Common Descent, all proteins are derived from other proteins, and ultimately from the minimal set present in the LUCA [Last Universal Common Ancestor], by descent-with-modification relationships (e.g., gene duplication).
Unfortunately, he ignores or overlooks the full paper from this group (Siew N, Fischer D. Analysis of singleton ORFans in fully sequenced microbial genomes. Proteins. 2003 Nov 1;53(2):241-51.)"The Total Number of ORFans in Microbial Fully Sequenced Genomes Continues to Grow (Fig. 1, Siew and Fischer 2003, p. 8)"
ie as you sequence more genomes, you find more relatives. This is what you would expect on the basis of evolutionary theory, and does not represent a problem for common descent (remember H. influenzae going from 64% of its ORF's being ORFans, to only 5.2% now as more genomes were added, this is the universal pattern for all organisms). Again he quotes Siew and Fischer minireview:From Siew and Fischer, Proteins: "We have shown that the number of ORFans is currently growing, whereas their fraction among ORFs is slowly diminishing."
But they also provide answers to their own questions, they say "There are two noteworthy observations about our ORFan database. The first is that over half of the ORFans are shorter than 150 residues. Possible explanations for this bias could be that some of the shorter ORFans may not correspond to expressed proteins [27], or that their abundance is a result of a limitation of computational sequence comparison; it is harder for current tools to detect sequence similarity for short sequences." In the larger paper, they also say:"If proteins in different organisms have descended from common ancestral proteins by duplication and adaptive variation, why is it that so many today show no similarity to each other?"
and again:"It is probable that some of the short ORFs are the result of random distributions of nucleotides, or of sequencing errors that lead to frame shifts and to wrong stop codons"
Nelson also cites Siew N, and Fischer D, (Unravelling the ORFan puzzle, Comparative and Functional Genomics 2003, 4, 432 -- 441.) in his blog entry as evidence of "A world class puzzle" (Siew and Fischer actually say it "entails interesting evolutionary puzzles"). But he ignores their analysis The authors say this:"Another possible reason for the abundance of short ORFans could be technical: It may be more difficult for sequence comparison programs such as BLAST22 to find significant matches for shorter sequences (see the work of Mackiewiez et al.26 for yet another possible explanation)." And there is evidence that a significant fraction of ORFans represent unrecognized divergen proteins (see below). They also say "ORFans may correspond to highly divergent sequences that actually belong to known families (but are beyond recognition capabilities of current tools),2 or to sequences that correspond to new, unique, single-member families."
Again, while we have no definitive answer to ORFans, they represent no threat to common descent, and we have several entirely reasonable explanations (that are proposed in the very publications Dr. Nelson cites). Lets summarise the main explanations: 1) Some ORFans may be artefacts. 2) Some ORFans may have relatives, but we haven't sampled enough genomes yet. 3) Some ORFans may have relatives, but our tools aren't good enough to detect these relatives yet. 4) Some ORFans may be de novo generated proteins. Now that was the state of play in 2003 (and remember, there was evidence for these explanations even then). Unsurprisingly, the field has moved on a bit and these explanations have been tested. Incidentally, these explanations were not pulled out of thin air, but had supporting evidence. Dr. Nelson doesn't mention these explanations in the powerpoint slides. Lets look at the explanations and some recent evidence. 1) Some ORFans may be artefacts: As noted above, many ORFans are very short, 100-150 codons long. It is likely that many of these represent database or annotation errors. Also, in any genome, one would expect some random ORFs being formed. Fukuchi S and Nishikawa K. (Estimation of the number of authentic orphan genes in bacterial genomes. DNA Res. 2004 Aug 31;11(4):219-31, 311-313.) closely examined sequences and estimated that about half of all short ORFans are sequencing or other errors. 2) Some ORFans may have relatives, but we haven't sampled enough genomes yet. While we have something like 150 complete bacterial genomes sequenced, there are many, many more bacteria that are not yet sequenced, and will have genomes quite divergent from the human pathogens that form the majority of current sequences. This will be especially important as horizontal transfer from a distantly related bacteria that has not been sequenced will look like an ORFan (until that distantly related bacteria is sequenced). A recent paper shows that many E. Coli ORFans are the result of horizontal gene transfer from bacteriophages (Daubin and Ochman, 2004; bacteriophages are viruses, which is why they don't turn up in bacterial database comparisons). 3) Some ORFans may have relatives, but our tools aren't good enough to detect these relatives yet. Siew and Fischer, not content to rest on their laurels having posed an interesting puzzle, have tried to solve on aspect of it. Using improved fold recognition software, and a larger database of fold family structures, they have found that in Bacillus sp, some related ORFans are members of the of the alpha/beta hydrolase superfamily, and most likely derive from the haloperoxidases (Siew et al., 2005). So evolutionary biologists have proposed a puzzle, suggested solutions to that puzzle, tested these solutions and largely confirmed them. Testing is by no means over yet, but all the evidence so far confirms that ORFans pose no threat to evolutionary biology. Indeed, if a large proportion of non-artefactual orphans are due to horizontal transfer from bacteriophages, as recent experiments suggest (Daubin and Ochman, 2004), then they may prove to be a valuable tool in understanding the phylogeny of bacteria, in the same way that families of LINES, SINES and pseudo genes have been. Far from being a threat to common descent, the patterns seen of the nested hierarchies of singleton, lineage specific and family specific ORFans are those you would expect from common descent. Some (very small number of) ORFans are also going to be de novo generated proteins. Biology is quite happy with the generation of new genes, it's a process we have seen and we don't demand all proteins come from the LUCA. In summary: Dr. Nelson has relied on some short review papers from 2003 to claim that ORFan genes are a threat to common descent. In fact, the data from these review papers, let alone the other research papers from this time, are fully compatible with common descent. To claim otherwise is disingenuous in the extreme. Papers published since these 2003 reviews were published have confirmed the major explanations for the origin of these ORFans, and supported the common descent model. Dr. Nelson would do well to examine recent literature, rather than selectively rely on old reviews. Even a cursory glance at the literature of the past two years would show that evolutionary explanations would suffice. References: Daubin V, Ochman H. Bacterial genomes as new gene homes: the genealogy of ORFans in E. coli. Genome Res. 2004 Jun;14(6):1036-42. Fukuchi S, Nishikawa K. Estimation of the number of authentic orphan genes in bacterial genomes. DNA Res. 2004 Aug 31;11(4):219-31, 311-313. Nurminsky DI, Nurminskaya MV, De Aguiar D, Hartl DL. Selective sweep of a newly evolved sperm-specific gene in Drosophila.Nature. 1998 Dec 10;396(6711):572-5. Okada H, Negoro S, Kimura H, Nakamura S. Evolutionary adaptation of plasmid-encoded enzymes for degrading nylon oligomers. Nature. 1983 Nov 10-16;306(5939):203-6. Siew N, Fischer D. Twenty thousand ORFan microbial protein families for the biologist? Structure. 2003 Jan;11(1):7-9. Siew N, Fischer D. Analysis of singleton ORFans in fully sequenced microbial genomes.Proteins. 2003 Nov 1;53(2):241-51. Siew N, Azaria Y, Fischer D. The ORFanage: an ORFan database.Nucleic Acids Res. 2004 Jan 1;32(Database issue):D281-3. Siew N, Fischer D.Structural biology sheds light on the puzzle of genomic ORFans. J Mol Biol. 2004 Sep 10;342(2):369-73 Siew N, Saini HK, Fischer D. A putative novel alpha/beta hydrolase ORFan family in Bacillus. FEBS Lett. 2005 Jun 6;579(14):3175-82."We propose the following model to explain the origin and abundance of ORFans and PCOs, which is somewhat consistent to the models discussed above. Many ORFans may have been generated as the result of a number of possible evolutionary events, which may include horizontal transfer, rapid evolution and gene-loss. ORFans (and other ORFs) without selection pressure have been deleted throughout microbial deletion mechanisms, and thus, microbial genomes are kept at 'reasonable sizes' [43]. ORFans that have retained or acquired an important function are kept, thus creating new sequence families with a seed of a single ORFan."
74 Comments
Glen Davidson · 26 April 2006
Anyhow, shouldn't something as "obviously designed" as the flagellum be the result of ORFan genes? Or don't IDists care about making real predictions, correlating evidence in comprehensible ways?
OK, those sorts of questions aren't even jokes anymore. "Intelligent design" is a set of disparate criticisms of real science, designed only to produce incoherence that they will claim is the result of "the designer". That is to say, the best result that these guys can imagine is a biology which proves not to make any sense. Unfortunately for them, the vast majority of biology makes sense even now, and we have only cause (trends) to suppose that more will in the future.
ID arose at a most unfortunate time for its proponents, the time when the old legitimate evidence became ever more correlated with the new DNA evidence. Far from being an alternative science, ID appears to merely react against the gains in knowledge that are occurring. So Nelson ignores the publication of human chromosomes with their inevitable evidence regarding our evolution via mutations, chromosomal rearrangements, and selection, while seeking for incoherence that he can ascribe to his God.
In the doing, his God becomes increasingly senseless and chaotic. IDists tell us that DNA has so many correspondences throughout living organisms because they have the "same designer", yet Nelson is claiming non-similarity as the actual evidence for this "designer". Thus they cannot keep their stories straight, nor show that any general characteristic of life is entailed by positing a designer of the sort that is known to produce actual designs.
And their "research" remains a mere mining of the literature coming out of real science, to emphasize whatever remains unknown. Apologetics has moved a long way from finding God in the workings of consistent and regular patterns within the "natural world".
Glen D
http://tinyurl.com/b8ykm
RPM · 26 April 2006
Drosophila provide a nice system for studying gene gain and loss due to excellent taxonomic sampling for genome sequencing projects in the D. melanogaster species group. For instance, this paper reports novel genes in a couple of species that do not have homologs in closely related species. And check out this article (it's just a news report, and it's not on Drosophila) which reports some other discoveries of de novo genes.
We'd expect most ORFans would encode small proteins -- the longer the gene, the lower the probability it evolves from scratch -- if they are not Intelligently Designed. Guess what? ORFans tend to have short protein coding sequences. For the example of Acps (Drosophila sperm accessory gland proteins), they are rapidly evolving genes with either low selective constraint or under strong positive selection. And they're tiny little proteins.
Paul A. Nelson · 26 April 2006
Hey Ian,
Good to see ORFans getting the attention they deserve. You misrepresented my slide, however. I said that "all proteins are derived from other proteins, and ultimately from the minimal set present in the LUCA [Last Universal Common Ancestor], by descent-with-modification relationships (e.g., gene duplication)." That is not equivalent to saying that all proteins originated in LUCA.
The number of microbial whole (completely sequenced) genomes is considerably higher than 150; NCBI gives 331 completed genomes at itsmicrobial page .
I strongly encourage readers here to pursue the ORFans puzzle on their own;this recent short review by Wilson et al. is a good place to start. And check out the global transposon mutagenesis paper by Glass et al . Ask yourself if Mycoplasma is likely to be the only prokaryote with 28 percent ORFans among its essential hardware.
Bill Gascoyne · 26 April 2006
Perhaps someday the people making these arguments (ORFans, bacterial flagellum, etc.) will have it drilled into their heads by their fundamentalist supporters that what it all boils down to is, "God left fingerprints that our ancestors could never have know about, and we're only now becoming clever enough to find them. Our ancestors had to rely on faith to know God, but we don't need faith anymore since we have scientific proof that God exists."
This is known, IINM, as an act of hubris.
k.e. · 26 April 2006
If God was created by man out of a desire for order as reflected in the seasons, the observations of the regular movements of the planets, a need to add heavenly authority to Kings for social regulation, collect taxes, make war and keep priests in a style of comfort to which they would not normally be accustomed if they had to work like everyone else then
Nelson's projection is that of a deranged, disordered, useless incoherent misanthrope.
An against mankind ad hominem attack on knowledge and truth.
A desperate clutching at tiny details while ignoring the overwhelming evidence of existing reality to push deluded misinformation for what purpose ? Oh that's right, the more ridiculous the claim the more he makes.
Create a class of people who have been programmed to reject facts and tell them that the more they are told they are wrong the more THAT PROVES they are right. When you have a captive audience just print the biggest load of rubbish you can and sit back and collect the money.
Paul A. Nelson · 26 April 2006
None of my links worked above. Here they are:
NCBI Microbial Genomes page:
http://www.ncbi.nlm.nih.gov/genomes/lproks.cgi
Glass et al. global transposon mutagenesis experiment in Mycoplasma (28 percent genes of unknown function among essential set):
http://www.pubmedcentral.gov/articlerender.fcgi?tool=pubmed&pubmedid=16407165
Wilson et al. survey of trends in the discovery of ORFans (roughly linear increase in number, with no sign of leveling off:)
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=16079329&query_hl=12&itool=pubmed_docsum
The OrphanMine is a good place to go exploring:
http://www.genomics.ceh.ac.uk/orphan_mine/orphan_home.php
Jim Wynne · 26 April 2006
Russell · 26 April 2006
A suggestion to consider for those ORFans that remain after the above hypotheses are explored. (Actually, it somewhat overlaps the above.)
Viruses, especially RNA viruses, evolve so fast it can make your head spin (relatively and figuratively speaking, of course). As a result, there is no shortage of "ORFans" in viral genomes, and I suspect there's no shortage of viruses we're not even aware of. These guys could transduce their extremely exotic genes to their hosts in rare lateral gene transfer events similar, for instance, to those thought to account for intronless pseudogenes (integration into the genome of a reverse-transcribed RNA).
'Rev Dr' Lenny Flank · 26 April 2006
Gee, it's too bad that by the time Paul's, uh, magnum opus is finished, ID will already be dead, buried and long forgotten. Like YEC already is. (shrug)
But hey, Paul, there are a few questions I have for you that you seem not to have answered yet.
They're at: http://www.geocities.com/lflank/nelson.html
steve s · 26 April 2006
Hey Paul Nelson, great to see you. I tried to tell these guys that ORFans had too much Ontogenetic Depth to have evolved, but they wouldn't listen to me. LOL.
PZ Myers · 26 April 2006
Glen Davidson · 26 April 2006
Ian Musgrave · 26 April 2006
Paul A. Nelson · 26 April 2006
None of my links worked above. Here they are:
NCBI Microbial Genomes page:
http://www.ncbi.nlm.nih.gov/genomes/lproks.cgi
Glass et al. global transposon mutagenesis experiment in Mycoplasma (28 percent sequences of unknown function among the essential cellular hardware):
http://www.pubmedcentral.gov/articlerender.fcgi?tool=pubmed&pubmedid=16407165
Wilson et al. survey of trends in discovery of ORFans (roughly linear increase in number, with no sign of leveling off:)
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=16079329&query_hl=12&itool=pubmed_docsum
The OrphanMine is a good place to go exploring:
http://www.genomics.ceh.ac.uk/orphan_mine/orphan_home.php
To Jim: the Glass et al. paper is freely available online. Note that the "unknown function" fraction in their experiment comprises essential sequences, an observation Ian doesn't treat in his post.
To PZ: of course, ex hypothesi, new proteins evolve throughout evolutionary time, commencing (under the theory of common descent) with the set present in LUCA. The problem is that on pretty much any theory of protein evolution, the origin of novel sequences will nevertheless leave an historical signal (homology as detected by sequence similarity). This is why ORFans are so puzzling.
'Rev Dr' Lenny Flank · 26 April 2006
Doc Bill · 26 April 2006
Sorry, Paul, but you have offered no evidence for your thesis whatsoever. Your argument is subjective at best, more likely specious.
As usual.
Ian Musgrave · 26 April 2006
delphi_ote · 26 April 2006
It's funny to listen to someone talk about the results of gene finders being evidence against common descent when the gene finding algorithms have statistical assumtions about common descent BUILT INTO THEM! These algorithms wouldn't work right if it weren't for common descent.
Silly, silly man.
Ron Okimoto · 26 April 2006
I'd like to ask Paul Nelson some questions. You seem to have a conscience. Why even put up an argument about ORFans? You've acknowledged that there is no scientific theory of ID, and that there never was one. So, you must understand that all you are doing is blowing smoke. Why even try? Shouldn't you be spending your time trying to make ID into something that is scientifically defensible? If you can't defend ID why blow smoke?
When did you know that the Discovery Institute had dropped ID for teach the controversy? West seems to have claimed that the Discovery Institute had a change of direction back in 1999. 1999 just happens to be when Meyer posted the junk about the legality of teaching the controversy. The Discovery Institute used to claim that ID was their business, but what is the business, now? I recall some of the Discovery Institute people bad mouthing Mike Gene when he came out and claimed that he didn't think that ID should be taught before Ohio broke. Did Mike just let the cat out of the bag too early? When were you informed of this change of direction and why didn't any of the fellows mention it to the general public? Why didn't anyone seem to know until Ohio? It certainly took the Ohio board by surprise. Before Ohio no one at ARN seemed to have a clue about the change except Mike.
Really, instead of blowing smoke, why not answer the questions?
steve s · 26 April 2006
Why not make ID scientifically defensible? Ron, Paul Nelson is a Young Earth Creationist. He can't make a silk purse out of a sow's ear. He can just try to badmouth real silk purses.
RBH · 26 April 2006
Anton Mates · 26 April 2006
'Rev Dr' Lenny Flank · 26 April 2006
Paul A. Nelson · 26 April 2006
Doc Bill · 26 April 2006
Thank you, Paul, for not answering my question.
I'll take that as an "I don't know what I'm talking about." answer.
Clearly, you spout typicall clueless creationist rubbish.
I am sorry for your dementia.
Russell · 26 April 2006
Bob O'H · 27 April 2006
Here's a stray thought wanting the attention of your electrons:
Would we expect to see more ORFans in bacteria that have higher frequencies of HGT (Horizonal Gene Transfer, not Hercules Grytpype-Thynne)? My reasoning is that with low HGT, it's more likely that an ORF will be derived from a similar gene in the same species, i.e. a gene that has already been sequenced. OTOH, with high HGT, it's more likely that the ORF has been picked up from some un-sequenced or unknown bacterium.
Bob
P.S. I'm disappointed at the lack of ORFul puns here.
PvM · 27 April 2006
Ian Musgrave · 27 April 2006
Frank J · 27 April 2006
Paul,
If ORFans are supposed to refute common descent, have you debated Behe on it?
PZ Myers · 27 April 2006
Flint · 27 April 2006
hiero5ant · 27 April 2006
Anton Mates · 27 April 2006
Whatever · 27 April 2006
Paul Nelson: I said that "all proteins are derived from other proteins, and ultimately from the minimal set present in the LUCA [Last Universal Common Ancestor], by descent-with-modification relationships (e.g., gene duplication)." That is not equivalent to saying that all proteins originated in LUCA.
It's still not true. There are cases where non-coding or frame-shifted sequences were exapted into other proteins. So, it's clear that some proteins were derived from non-protein encoding sequences.
Ian Musgrave: ... yet, we do find hierarchical families of ORFans with historical traces, just as if they evolved.
That's the kicker that really damages Dr. Nelson's position on this subject. ID thinking must acknowledge that there are at least two types of ORFans -- Those found only in one species/breed and those found across multiple groups in hierarchical families. But if I hand Dr. Nelson a set of ORFan sequences and provide no further information, he has *no means* of deciding which ORFans are unique only to a single species. A potential IC research program?
I invite ID theorists to consider additional implications of ORFans, not simply as an anti-evolutionary argument, but the opportunities they present for investigating potential 'acts' of design and the manner & mode of a hypothetical designer. I would think the design community would be excited over the research opportunities. For starters, many of these ORFans could be fairly recently 'inserted' by a designer into freshly created species. They would be the some of the more experimentally tractable design artifacts to investigate and theorize about (e.g. less time for sequence divergence to wipe out important signals). Finally, a chance to do real science!
Here's another thing: Based on an ID-friendly notion that ORFans are specifically tailored and inserted in distinct events, I propose that the designer is still very active -- Different populations that can interbreed have distinct ORFans of their own. This suggests that ID 'intervention' extends *below* the level of species. An interesting nettle for baraminology, I'd muse.
Aside #1: 50 quatloos says this golden opportunity will be squandered.
Aside #2: ORFans tend to be short. I wonder why the designer prefers short unique sequences. A possible design constraint worth investigating? Will we see this investigated in a future work by Drs. Behe, Wells or Dembski?
Anton Mates · 27 April 2006
Don Baccus · 27 April 2006
Glen Davidson · 27 April 2006
Tyrannosaurus · 27 April 2006
Paul Nelson posted
To PZ: of course, ex hypothesi, new proteins evolve throughout evolutionary time, commencing (under the theory of common descent) with the set present in LUCA. The problem is that on pretty much any theory of protein evolution, the origin of novel sequences will nevertheless leave an historical signal (homology as detected by sequence similarity). This is why ORFans are so puzzling.
Of course they are puzzling but nonetheless amenable to study and discern of their origins and evolution. However the insistence on homology as detection of origin and evolution fails to consider that through the billions of years of history the divergence could be so great as to render the recognition of homologies a very tasking endeavor indeed. Since the divergence in function and sequence can grow to such extends, it is very difficult to know where to look for the homologies. That is, the differences can be obscured to such a degree that only through painstaking labor and years of collecting sequences we will be able to start assembling the patterns of recognition. Is that a contradiction or a show stopper in research? The answer is no. Is this a puzzle that evolutionary theory cannot answer? Again the answer is no.
mike syvanen · 27 April 2006
AC · 27 April 2006
T.M · 27 April 2006
I have been wondering (for many years) why educated scientists have consistantly been using the term "evolution" to descibe small biological changes in organisms, such as the nylonase, when it is clearly an example of ADAPTATION? No new lifeforms have been created, only a variation of an existing lifeform.
ah_mini · 27 April 2006
Don Baccus · 27 April 2006
Russell · 27 April 2006
steve s · 27 April 2006
While we're all having a good laugh about Paul Nelson's latest jibber-jabber, take a minute to go back in history and read about his classic failure, Ontogenetic Depth.
gwangung · 27 April 2006
I have been wondering (for many years) why educated scientists have consistantly been using the term "evolution" to descibe small biological changes in organisms, such as the nylonase, when it is clearly an example of ADAPTATION? No new lifeforms have been created, only a variation of an existing lifeform.
Because new species HAVE been created.
Pay attention, trolls; you'll be a LOT more effective if you keep up with the literature and not just regurgitate old creationist propaganda indiscriminately.
'Rev Dr' Lenny Flank · 27 April 2006
Frank J · 27 April 2006
Tyrannosaurus · 27 April 2006
T.M. cluelessly wrote;
No new lifeforms have been created, only a variation of an existing lifeform.
And that is called evolution. Now that you Creos admit to it, that lifeforms have not been created, why do you keep on squealing? (shrug)
DJ · 27 April 2006
ID is just so cute.
Half its proponents accept Common Descent but insist that an intelligent agent has something to do with it. This bunch accepts that similar DNA in similar species is because of common descent but they feel "design" is detectable in the unknowns.
Then the other half constantly argues against Common Descent. They explain the nearly identical DNA of what we would call closely related species as an indication that the "designer" simply uses the same building materials. Just, only, in a way that makes it look precisely like Common Descent.
Funny now that Paul Nelson is saying that dissimilarity of ORFans is also evidence of a designer and is "trouble" for Common Descent. Now the designer supposedly uses fresh building blocks all over the place too.
But I suppose this still means that any ORFan families that get identified over time will be further evidence of the designer using similar building blocks. Just, only, in a way that makes it look precisely like Common Descent.
The Big Tent o' Contradiction makes me dizzy.
Henry J · 27 April 2006
Glen,
Re "[...] and accept models that reduce the anomalies as far as possible."
Hey, that could be another way of describing the scientific method - a search for principles that minimize the number of anomalies.
-------------
T.M.,
Re "I have been wondering (for many years) why educated scientists have consistently been using the term "evolution" to describe small biological changes in organisms, such as the nylonase, when it is clearly an example of ADAPTATION?"
My guess is it's for the same reason that the word "movement" is applicable to both movement over a millimeter and to movement over a kilometer.
Re "No new lifeforms have been created, only a variation of an existing lifeform."
That line pretty much summarizes evolution - all lifeforms beyond the simplest are "only" variations of previous lifeforms.
Henry
Ian Musgrave · 27 April 2006
Coin · 27 April 2006
While I still see no reason ORFans are a problem for evolution, it does seem to me the presence of ORFans pose serious problems for the "front loading" theory adopted by some creationists. The theory of evolution, it would seem, would logically predict that some bounded proportion (more than zero, but not too much) of all genes be ORFans in the sense of being genes which are not related to those of any other species. I would call this a reasonable prediction because there are multiple routes by which mutation can occur besides wholesale duplication, and while the likelihood may be lower, there is nothing stopping new genetic coding from occuring (leaving real-world evolutionary theory resting comfortably between the "all proteins must be derivatives of the ones in the LUCA set" straw man model of evolution we see in this discussion and the "junkyard in a tornado" straw man model of evolution seen in other discussions). Front loading theory, however, implicitly rejects this idea, asserting that all "important" information was present in the genome from the very beginning and some of this information just took awhile to activate. Would it not be reasonable to say that ORFans are some level of disproof, or at least a predictive failure, of front loading theory?
Indeed, the presence of ORFans would seem to be a serious problem for any of the many strains of creationists that claim mutation "cannot add information", since ORFans (at least those that don't turn out to be just illusions caused by inaccurate sequencing or relationships we can't detect), when they code for proteins would seem to be snapshots of a process of information being added to the genome itself. Some creationists insist that all emergence of new traits that have been observed by scientists are adaption, not entirely-new mutation; but the entire problem with ORFans is that they cannot be explained by adaption rather than entirely-new mutation.
Am I incorrect in my analysis of the situation above?
Could it be that Nelson's writings on this subject, though we have seen they fail to refute or even really address the theory of evolution, are in fact potent arguments against other creation science and intelligent design theories?
Popper's Ghost · 28 April 2006
McA · 28 April 2006
Lets summarise the main explanations:
1) Some apparent fossil chains may be artefacts.
2) Some creatures may have no ancestors, but we haven't sampled enough fossil beds yet.
3) Some creatures may have no ancestors, but our tools aren't good enough to detect these fossils yet yet.
4) Some apparent fossils may be spontaneously created but just look like fossil chains....
Whatever · 28 April 2006
Ian Musgrave: "Now, given the data in the papers above, and given that at least Dan is relatively knowledgeable about genes, I will bet you a bottle of Australian Red (high in beneficial resvertarol and other polylphenolics, as well as being a mite tasty) that they actually came up with a perfectly testable hypothesis, perhaps even made testable predictions."
Interesting. Evolutionary theory and basic chemistry provided a productive framework for posing hypotheses about the origin of ORFan sequences. Some of these proposed explanations involve simple, mundane artifacts, such as sequencing errors or current catalogs missing sufficient information. Others involve the nature and turnover of sequences in the genome. There are multiple explanations because there are multiple mechanisms which could create sequences we group as ORFans. Many of these hypotheses have been confirmed. Can all that work really be dismissed as 'handwaving'? Is the notion of common descent such a useless idea as many IDer's suggest?
Where does ID fit in the picture for investigating the origin of ORFans? Where is the ID research program for ORFans?
steve s · 28 April 2006
Lynn · 28 April 2006
Quoting mike syvanen on April 27, 2006 12:42 PM (e):
"anton wrote:
This is more a historical observation than anything, but Darwin didn't have a single tree. He thought it was possible that there were multiple independent origins of life.
"There is grandeur in this view of life, with its several powers, having been originally breathed into a few forms or into one...""
Yes this is quite interesting. It seems that Darwin's thinking was likely influenced by Lamarkian thought on multiple origins of life. It was later, after the deserved demise of Lamarkian evolution, that the single tree concept took hold. With the rise of the cladists the possibility of polyphyletic origins became downright blasphemous."
This doesn't at all follow. Taking into account Darwin's almost complete lack of knowledge of the cellular and physiological similarities of, eg, plant and animal life, it would have been perfectly reasonable for him to consider it pretty likely that two such different seeming kinds of life had separate origins.
Lynn
mike syvanen · 28 April 2006
mike syvanen · 28 April 2006
Popper's Ghost · 28 April 2006
Popper's Ghost · 28 April 2006
mike syvanen · 28 April 2006
mike syvanen · 28 April 2006
Popper's Ghost · 28 April 2006
CJ O'Brien · 28 April 2006
The way I understand it, a Lamarckian model would have not several, roughly simultaneous, ancient origin events, but continuous origin events, as new lineages start the 'climb up the ladder.'
Any way, that's how I have geerally conceptualized the fundamental difference between Darwinian and Linnean thought: branching bush with single stem vs. multiple, parallel 'ladders.'
Frank J · 28 April 2006
CJ O'Brien · 28 April 2006
For "Linnean" in my prev. comment, please read "Lamarckian."
those typing fingers have a mind of their own sometimes.
mike syvanen · 30 April 2006
Martha B · 2 May 2006
Paul Nelson quotes Russell Doolittle; Russel Doolittle says, "After more than a century of study by biochemists and microbial geneticists how could there be so many unrecognizable genes?"
Excuse me, but what century is he talking about? It's been only about a century since biologists recognized inheritance was discrete and things called genes even existed. It's been just over 50 years since Watson and Crick discovered the structure of DNA, and it took several years after that for their model to be accepted. The genetic code wasn't fully cracked until around 1967. Rapid methods for working out complete genomes didn't exist until the turn of the present millenium. Of course, if Doolittle had said something like, "It's been, oh, around a week and a half since there have been any major advances in biology. How could there still be unanswered questions about evolution?" he wouldn't have sounded nearly as impressive, and Nelson wouldn't have bothered to quote him. But at least he would have been honest.
Anton Mates · 2 May 2006
Glen Davidson · 2 May 2006
Ian Musgrave · 2 May 2006