Amphioxus and the evolution of the chordate genome

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This is an amphioxus, a cephalochordate or lancelet. It's been stained to increase contrast; in life, they are pale, almost transparent.

amphioxus.jpg

It looks rather fish-like, or rather, much like a larval fish, with it's repeated blocks of muscle arranged along a stream-lined form, and a notochord, or elastic rod that forms a central axis for efficient lateral motion of the tail…and it has a true tail that extends beyond the anus. Look closely at the front end, though: this is no vertebrate.

amphioxus_closeup.jpg

It's not much of a head. The notochord extends all the way to the front of the animal (in us vertebrates, it only reaches up as far as the base of the hindbrain); there's no obvious brain, only the continuation of the spinal cord; there isn't even a face, just an open hole fringed with tentacles. This animal collects small microorganisms in coastal waters, gulping them down and passing them back to the gill slits, which aren't actually part of gills, but are components of a branchial net that allows water to filter through while trapping food particles. It's a good living — they lounge about in large numbers on tropical beaches, sucking down liquids and any passing food, much like American tourists.

These animals have fascinated biologists for well over a century. They seem so primitive, with a mixture of features that are clearly similar to those of modern vertebrates, yet at the same time lacking significant elements. Could they be relics of the ancestral chordate condition? A new paper is out that discusses in detail the structure of the amphioxus genome, which reveals unifying elements that tell us much about the last common ancestor of all chordates.

But first, a little question that needs to be resolved. This is an ascidian, a member of the subphylum urochordata.

ascidian-amphioxus.jpg

Like us and like amphioxus, it also has a central notochord, and it also has segmental blocks of muscle and a dorsal nerve cord, and in this case you can also see that it has an expansion of the front of the nerve cord into something that looks rather brain-like. Ascidians are also more diverse and successful than the cephalochordates.

A major difference, though, is that amphioxus maintains its chordate morphology throughout its life — the picture at the top of this page is an adult. Ascidians, on the other hand, only look like tadpoles in their larval stages, which is only a dispersal form. They swim away from their parent and settle down on a solid surface and throw away their tail and brain and squat permanently as a sessile filter feeder called a sea squirt. This opens a debate about chordate ancestry. Did we 1) evolve from an ascidian-like animal, that maintained it's larval stage throughout life and refined its form to become something like an amphioxus, which then evolved into the vertebrates? Or was 2) an amphioxus-like animal at the base of the family tree, and the ascidians are the weird cousins who went off and evolved a specialized adult form?

I've discussed ascidian evo-devo before, and the consensus so far is that the second model is most likely, and ascidians are a highly derived descendant of the last common ancestor of all chordates, which have gone off in some radical and very interesting directions. The current paper on the amphioxus genome confirms that, and in particular reveals an interesting fact: while the ascidian genome has undergone some major remodeling that makes it very different from our own, the amphioxus genome seems to have conserved many ancestral features and may very well be a good proxy for examining the genetics of the last common chordate ancestor.

Before we move on to the genetics, though, look at the diagram above. At the bottom are two embryos at the 8-cell stage, with the prospective fates of some regions marked: cells that form in the area with the horizontal hatching will become notochord, and those with the vertical hatching will become the neural tube. The two are very similar; the one on the left is an ascidian embryo, and the one on the right is an amphioxus embryo. Both exhibit a pattern of mosaic development, in which the fates of regions of the egg are mapped out by a pre-pattern of molecular determinants. Vertebrates do not do this, or do so to a much lesser degree; we have regulative development, in which early cells are much more plastic, and gradually and progressively determine their role in the embryo. This suggests, though, that mosaicism may be an ancestral property of the chordate lineage, and we are the weirdos who have departed far from the traditional pattern in this regard.

Let's also have a brief video interlude. Below is a time-lapse movie of amphioxus development. You'll see the 8-cell stage illustrated above, and then it flies through a series of transformations into a hollow ball, folding in a portion of the structure to make a cup-shape organism, then elongating to make a kind of canoe-shaped beast, which then differentiates the various muscles and tissues to make an embryonic amphioxus. Isn't it lovely?

The recent paper in Nature by Putnam and others describes the completion of the draft genome sequence for the amphioxus species, Branchiostoma floridae. The genome is about 520 megabases long (a sixth the size of ours) and contains about 22,000 protein coding regions, or genes, and so is about the same size as ours. All this data means that a better phylogenetic tree can be assembled, which is shown below and which supports the conclusion that amphioxus diverged early in chordate history, followed by a later split between the urochordates and the vertebrates.

chordate_clade.jpg
(click for larger image)

Deuterostome phylogeny. Bayesian phylogenetic tree of deuterostome relationships with branch length proportional to the number of expected substitutions per amino acid position, using a concatenated alignment of 1,090 genes. The scale bar represents 0.05 expected substitutions per site in the aligned regions. Long branches for sea squirt and larvacean indicate high levels of amino acid substitution. This tree topology was observed in 100% of sampled trees. Numbers in red indicate bootstrap support under maximum likelihood. Unlabelled nodes were constrained.

Look at the magnitude of the substitutions in the urochordates! If you want to argue that any chordate group is "more evolved" than any other, you'd have to hand the title to those somewhat obscure organisms — they've been shedding genes and reorganizing and adapting in some amazing ways.

Now for the tricky part, the analysis of synteny. If you're not familiar with the concept, you might want to review yesterday's basic summary of synteny, but it is basically a search for conserved clusters of genes. In this work, they used the logic of synteny to work out the existence of 17 ancestral Chordate Linkage Groups (CLGs). A CLG may roughly compare to a single chromosome in the chordate last common ancestor — it's a set of genes that are associated with one another in multiple species, and are thought to represent the retention of an ancient organization.

Here's the wonderfully complicated summary diagram.

amph_hum_synteny.jpg
(click for larger image)

Quadruple conserved synteny. Partitioning of the human chromosomes into segments with defined patterns of conserved synteny to amphioxus (B. floridae) scaffolds. Numbers 1–17 at the top represent the 17 reconstructed ancestral chordate linkage groups, and letters a–d represent the four products resulting from two rounds of genome duplication. Coloured bars are segments of the human genome, shown grouped by ancestral linkage group (above), and in context of the human chromosomes (below).

First, along the top they have reconstructed the 17 ancestral CLGs, and they've color-coded them: for instance, the genetic contents of CLG #8 (or ancestral chromosome #8, if you'd rather think that way) has been deduced from a comparison of human and amphioxus genomic data, and all those genes have been colored yellow. Below the ancestral CLGs is a diagram of the human chromosome set, from chromosome 1 to 22, with the X chromosome, and homologs to each of the genes in CLG #8 have also been colored yellow. You can see that ancestral chromosome 8 has, over the 500+ million years since, broken up and scattered into human chromosomes 2, 4, 5, 11, 13, and X.

I have to qualify this image a bit, though: don't get the impression that big chunks of the ancestral chromosomes have survived perfectly intact for half a billion years! What's illustrated here is a pattern of macro-synteny — what it says is that within a swathe of a particular color, we can find many, but not all genes that can be mapped to a common linkage group. If we did a more fine-grained synteny diagram, where we only mapped continuous blocks of 3 or more genes that were the same, we'd have a much messier, more salt-and-pepper sort of picture.

Within a region of a single color, there has been much scrambling of the local gene order. There have also been additions of individual new genes in either the amphioxus or human genome, and losses of genes. Also, not all genes are included in this summary: approximately 60% of the human genes that have amphioxus orthologs are found in these linkage groups. What each bit of color means is that this is a region that is enriched for a common set of shared genes between amphioxus and human beings, but it has also been leavened with variation and scrambled about internally. What has been preserved is not a literal duplicate of an ancient chromosome, but a segment that retains enough signal above the noise of ages of slow rearrangement that we can detect its affinities.

Still, pretty cool, I think. Evolutionary change hasn't completely swamped out our origins, only made them fainter and trickier to discern.

There is one other significant detail to this illustration. If you look at the ancestral CLGs, you see that each has more than one colored bar descending from them — there's four for each. What's going on here? For each gene (more or less) identified in amphioxus, there tend to be multiple genes in the human. When aligning them, you'll get multiple roughly equivalent sets of genes lining up with each amphioxus group. What this reveals is that our history is marked by two rounds of whole genome duplications after we branched away from amphioxus. This is also very cool; it might explain some of the greater diversity we see in later chordates, that they have more potential for new combinations and variations of genes.

You might recall that I mentioned that humans and amphioxus have approximately the same number of genes, about 20,000, and be wondering how that jibes with the evidence that there were 2 rounds of duplications. Shouldn't we have four times as many genes? The answer is no. When a gene is duplicated, more often than not is that one of the copies will accumulate errors and drift away into nonexistence.

Imagine that we have a stretch of chromosome that has these genes on it:

A-B-C-D

A duplication occurs; now we have two regions:

A-B-C-D and A'-B'-C'-D'

Errors take out some of the copies, so we end up with this:

A-.-C-. and .-B'-.-D'

Now, you see, we've got a result where the organism hasn't gained or lost anything overall — it still has an A, B, C, and D gene — we haven't had a doubling of the total gene numbers, we still have four genes. If we look at the synteny, we'd see one stretch of chromosome, A-.-C-., that lines up with the ancestral A-B-C-D, and we'd also see a second region, .-B'-.-D', that also lines up with it — there'd be two matches. Even though we haven't seen a significant net increase in gene numbers, we still have a doubling of the number of syntenic regions.

That's what this paper is reporting: no major increases in the number of genes, but we are seeing the vestiges of that ancient doubling. Furthermore, the losses aren't entirely random. There has been a preferential retention of duplicate genes involved in signal transduction, transcriptional regulation, neuronal activity, and developmental processes, exactly what we'd expect to see if new avenues in developmental and behavioral complexity were being explored by our ancestors. So what probably happened is that there was a fairly abrupt duplication event in our history that was largely neutral in its initial effect, and was gradually pared back down, but that some of the duplications generated new capabilities that were promoted by natural selection.

Before our ancestors were even fish, they were Cambrian and pre-Cambrian filter-feeding torpedos, muscular tubes with springy tails that darted through clouds of bacteria and plankton in the seas, harvesting microorganisms in a branchial net, and that probably resembled modern amphioxus more than anything else. That was our primitive niche, motile grazers on suspended particles. Where we vertebrates came from was an accidental set of duplications that created new combinations of genes and new phenotypic variants, some of which had adaptive advantages.

Don't get too cocky and think that surges in complexity are always a good thing, and lucky for us that we are the outcome. Evolution is blind and sometimes the fortunate result can go the other way: look to the ascidians, which, rather than expanding their genetic library, have been successful by streamlining their genomes, chucking out unnecessary elaborations and juggling a smaller suite of genes around in more dramatic ways. There are many directions evolution can take, and there's no a priori reason to think our particular path is the most powerful.


Putnam NH, Butts T, Ferrier DE, Furlong RF, Hellsten U, Kawashima T, Robinson-Rechavi M, Shoguchi E, Terry A, Yu JK, Benito-Gutiérrez EL, Dubchak I, Garcia-Fernàndez J, Gibson-Brown JJ, Grigoriev IV, Horton AC, de Jong PJ, Jurka J, Kapitonov VV, Kohara Y, Kuroki Y, Lindquist E, Lucas S, Osoegawa K, Pennacchio LA, Salamov AA, Satou Y, Sauka-Spengler T, Schmutz J, Shin-I T, Toyoda A, Bronner-Fraser M, Fujiyama A, Holland LZ, Holland PW, Satoh N, Rokhsar DS (2008) The amphioxus genome and the evolution of the chordate karyotype. Nature 453(7198):1064-71.

35 Comments

Da-da da-dum-dum-dum:

It’s a long ways from amphioxus, it’s a long ways to us. It’s a long ways from amphioxus, to the meanest human cuss. Well, it’s good-bye to fins and gill slits, And it’s welcome lungs and hair. It’s a long, long way from amphioxus But we all came from there.

– fight song of the University of Ediacara (Phil Pope)

White Rabbit (Greg Goebel) http://www.vectorsite.net/tadarwin.html

This was an excellent article for Intelligent Design; to wit, the components of the branchial net allows water to filter through while trapping food particles. Functions exactly as it was designed. I’m simply amazed at creation. THE BIGGER PICTURE IN THE DEBATE ON DARWINISM IS NOT INTELLIGENT DESIGN. The reason is elementary: the Discovery Institute and other ID proponents leave out the Triune God, Father, Jesus, and the Holy Spirit. Hence, Richard Dawkins can make the case for “aliens” seeding the earth. The Quest for Right, a series of 7 textbooks created for the public schools, represents the ultimate marriage between an in-depth knowledge of biblical phenomena and natural and physical sciences. The several volumes have accomplished that which, heretofore, was deemed impossible: to level the playing field between those who desire a return to physical science in the classroom and those who embrace the theory of evolution. The Quest for Right turns the tide by providing an authoritative and enlightening scientific explanation of natural phenomena which will ultimately dethrone the unprofitable Darwinian view. “I am amazed at the breadth of the investigation - scientific history, biblical studies, geology, biology, geography, astronomy, chemistry, paleontology, and so forth - and find the style of writing to be quite lucid and aimed clearly at a general, lay audience.” ― Mark Roberts, former Editor of Biblical Reference Books, Thomas Nelson Publishers.

The Quest for Right series of books, based on physical science, the old science of cause and effect, has effectively dismantled the quantum additions to the true architecture of the atom. Gone are the nonexistent particles once thought to be complementary to the electron and proton (examples: neutrons, neutrinos, photons, mesons, quarks, Z’s, bosons, etc.) and a host of other pseudo particles. To the curious, scientists sought to explain Atomic theory by introducing fantastic particles that supposedly came tumbling out of the impact between two particles, when in fact, the supposed finds were simply particulate debris. There are only two elementary particles which make up the whole of the universe: the proton and electron. All other particles were added via quantum magic and mathematical elucidation in an attempt to explain earthly phenomena without God. Introducing the scheme of coincidence, which by definition, “is the systematic ploy of obstructionists who, in lieu of any divine intervention, state that any coincidental grouping or chance union of electrons and protons (and neutrons), regardless of the configuration, always produces a chemical element. This is the mischievous tenet of electron interpretation which states that all physical, chemical, and biological processes result from a change in the electron structure of the atom which, in turn, may be deciphered through the orderly application of mathematics, as outlined in quantum mechanics. A few of the supporting theories are: degrading stars, neutron stars, black holes, extraterrestrial water, antimatter, the absolute dating systems, and the big bang, the explosion of a singularity infinitely smaller than the dot of an “i” from which space, time, and the massive stellar bodies supposedly sprang into being. The Quest for Right is not only better at explaining natural phenomena, but also may be verified through testing. As a consequence, the material in the several volumes will not violate the so-called constitutional separation of church and state. Physical science, the old science of cause and effect, will have a long-term sustainability, replacing irresponsible doctrines based on whim. Teachers and students will rejoice in the simplicity of earthly phenomena when entertained by the new discipline. The Quest for Right. http://questforright.com

Great post, PZ. Kudos on the splendid bio-illuminations and ruminations.

Although I’m puzzled by what the neutron-denying ID-puffing poster thinks about the relevance of his commercial appeal to your topic. My guess is he doesn’t. (Think). Nuff said. DNFTT. Dave

Another excellent article from PZ. The man is good, I tell you. Not God. At least, not yet.…

Don’t feed the trolls … don’t feed the trolls … don’t feed the trolls.

But they seem like they’re starving for someting.

Nevermind. Don’t feed the trolls.

So my sister group wears a squirt, eh?

Dave Thomas said:

Although I’m puzzled by what the neutron-denying ID-puffing poster thinks about the relevance of his commercial appeal to your topic. My guess is he doesn’t. (Think).

Neuron-denying?

Say neocortex denying and I can understand the affinity to amphioxus.

(sigh) Articles like this make me wish I could turn the clock back 35 years and choose biology, with chemistry only as a “second major.” The endless jargon, which turned me off to bio back then, is still there, but now at least we have the proverbial “pictures worth 1000 words.”

As for the trolls, every day that they (1) avoid doing their own research, (2) mine the literature for raw material to “support” their incredulity arguments, and (3) cover up or otherwise downplay their own irreconcilable differences as to what the designer did, when and how, is another virtual admission that, design or no design, it’s still evolution, common descent, and a ~4-billion year history of life.

Thanks for this lucid summary of the Nature paper.

My Mosque is putting out a series on the bigger picture about the Christian Infidels at the Discovery Institute and their blaspheming tripe on ID. God is Great!

C. David Parsons said:

To the curious, scientists sought to explain Atomic theory by introducing fantastic particles that supposedly came tumbling out of the impact between two particles, when in fact, the supposed finds were simply particulate debris.

What then is the “debris” made of? ;)

Torbjörn Larsson, OM said:

Neuron-denying?

I think it’s a type for neutron-denying.

Torbjörn Larsson, OM said:

So my sister group wears a squirt, eh?

Dave Thomas said:

Although I’m puzzled by what the neutron-denying ID-puffing poster thinks about the relevance of his commercial appeal to your topic. My guess is he doesn’t. (Think).

Neuron-denying?

Say neocortex denying and I can understand the affinity to amphioxus.

No, I meant neutron-denying, as shown by this snippet:

There are only two elementary particles which make up the whole of the universe: the proton and electron.

But the actual effect may indeed be neuron-denying, as you say.

Dave

“Neuron-denying.” Now, that is funny.

 

I am always amazed at an evolutionist attempting to explain a fundamental aspect of creation. To wit, complications persist whenever the term simple is used to tag any creature of procreation. Simple means “consisting of few parts (not complex), a lower order; also, genesis, in the sense of a beginning or origination.” In consideration of the true, all unicellular organisms are immensely complex, solitary life forms consisting of millions of molecules functioning together to form a whole. Hence, referring to complex creatures as simple defies all logic. Further complicating the issue, a so-called unicellular (one cell) organism does not consist of a single cell but a great configuration of cells. Each cell has been mathematically projected to have a memory potential of about 10(22) bits, sufficient to store the information contained in several million books. Although the projection of a single cell’s memory potential is an incredulous amount, the informational equivalent is still great, especially when a more realistic number is multiplied by the total number of cells making up a simple life form. In short, the supplanting of the term simple for complex is idealistic in that it supposes that a life form is simple purely because of its microscopic size. Moreover, the prejudice of the language paves the way for a similar but more complex cell to be rated a higher transition, thus, opening up an unwarranted avenue for the promotion of protracted graduation.

 

The seemingly inoffensive colloquialism incorporated by biologists is far from innocent: its repetitious usage in books, films, and the like acts like a subliminal message upon the subconscious, becoming more ingrained and effective with each repetition. The message is in itself simple: all supposedly higher life forms initially developed from a simple unicellular organism. The hypothesis, if valid, only serves to raise the greater issue as to how the first microscopic cell gained its projected memory potential of 1022 bits, thereby, establishing the elaborate genetic code by which all of life is governed.

 

A prime example of the abuse of terminologies or, more specifically, a misapplication of terms, is the use of primitive to describe certain creatures, as the little amoeba. The term is used in the sense of “existing from the beginning or deviating very little from the earliest ancestors.” The amoeba is held to be primitive, due in part to (1) its unique expression of locomotion, and (2) to a lack of deference (respect) for the little creature’s remarkable inherent abilities which, heretofore, have not been understood.

 

An amoeba may be identified by its constantly changing freeform appearance. The creature forms temporary cytoplasmic extensions, mislabeled pseudopodia-“false feet,” by which it gains mobility. The appendages, however, may not be called feet in any sense of the word. In effect, the microscopic organism, endowed with a most clever trait of creation, gains mobility, not by “walking about,” as supposed, but by weight distribution. The appendages are, in reality, tracks, the means by which the amoeba ingenuously transforms itself into a treadmill, gaining mobility by distributing its weight in the direction of travel. The proper terminology for the amoeba’s unique form of locomotion is treadmill; the misnomer pseudopodia is deleted in favor of the more encompassing tracks. The unjustifiable labeling of the remarkable amoeba as primitive may seem to some to possess a quality of irony in that the secret of its locomotion has previously remained a closely guarded secret. In fact, the amoeba has given up few of its secrets; for example, its forging effort is routinely governed by inherent conditioning or behavior patterning. An amoeba has neither a mouth nor a stomach, but, when a particle of food comes in contact with any portion of its membrane (outer covering), a cytoplasmic appendage envelopes the food, forming a digestive chamber or vacuole, wherein a gastric juice is secreted to digest the food so that it may be assimilated (absorbed) into the body. In addition, the amoeba has neither an anus to discharge metabolic wastes nor a respiratory organ to take in oxygen; metabolic wastes are diffused outward through its membrane while oxygen diffuses in from surrounding water in which the remarkable creature thrives.

 

In an adverse environment, the inherent conditioning initiates a protective countermeasure to ensure the survival of the species. The amoeba expels most of its fluid, forms a tiny ball, and secretes a cyst, a protective envelope that resists both freezing and dehydration. When the adverse condition is reversed, the amoeba sheds the membrane and emerges once again.

 

While the measure for survival may appear to be relatively simple, there is more to the phenomenon than biologists have accredited. The “cyst” is in fact a protein sepulcher, the means by which the amoeba entombs itself in an adverse environment. During the entombment, the once constantly freeforming creature is immobilized; however, its inherent conditioning remains active. The environment is continuously tested, or monitored, until such time as its watery home is found to be safe. The amoeba does not reemerge, as previously surmised. Instead, the fascinating creature goes through a metamorphosis of sorts in which it will remain an encrustation adhered to the inside of its protein sepulcher. The amoeba that emerges is a new individual, regenerated, “formed anew,” from the original parent. The new individual buds forth as an outgrowth of the parent’s body in a type of asexual reproduction complementary to fission. The emerging amoeba casts off the protein sepulcher, along with the encrustation of its parent’s body inside, and begins to treadmill about in search of food, deceiving man as to its true heritage in the process. If the environment sanctions an entombment of the new individual, the process is repeated. A new offspring will bud forth to take the place of the entombed parent; thus, ensuring the survival of the species.

 

NOTE: The diet of an amoeba includes plankton. Little is known about the species: plankton is considered primitive by biologists.

 

The inspiring little amoeba, in that it is among the smallest creatures of procreation, yet equipped to survive in an often adverse environment, has reluctantly given up two of its most jealously guarded secrets: its unique expression of locomotion and the ability to entomb itself, regenerating a new individual in the process. The remaining functions of the multifaceted, highly complex organism, for example, the contractile vacuole, central granular endoplasm, granular nucleus, and other transparent organs as well as numerous metabolic functions, governed by an elaborate genetic code, remain the well guarded secrets of the amoeba. In the grand scale of the environment, the marvelous amoeba fits nicely into its ecological niche. With its former respect restored, to the embarrassment of biologists, the amoeba may no longer be called either primitive or simple in any sense of the word. It remains, therefore, that the combined wisdom of man is impotent in explaining any but the most so-called simple aspects of procreation. Copyright 2008, The Quest for Right.

 

C. David Parsons, author of The Quest for Right. http://questforright.com

Can we have a little troll-cleaning please? We’ve become infested again.

I am always amazed at an evolutionist attempting to explain a fundamental aspect of creation …

It really is true! You can indeed find decaffienated coffee that tastes as good as the real thing.

White Rabbit (Greg Goebel) http://www.vectorsite.net/tadarwin.html

…[A] so-called unicellular (one cell) organism does not consist of a single cell but a great configuration of cells.

Hmmmm…

Each cell has been mathematically projected to have a memory potential of about 10(22) bits…

Ohhhh?

The diet of an amoeba includes plankton.

Weeeeeee!

…the well guarded secrets of the amoeba.

Heh.

1158 words.

And yet not one single good solid point.

stevaroni said:

1158 words.

And yet not one single good solid point.

That’s because B.S. volume is proportional to (word count)^3

Must admit, I’ve found the internet to be hilariously full of all manner of deniers. Global warming deniers, evolution deniers, HIV/AIDS deniers and even a few round earth deniers but I have to admit I’ve never met a neutron denier before. Parsons here may indeed have founded a whole new species of internet crackpottery. Perhaps the evolutionary biologists really are on the wrong track and should study speciation in bullshit instead of living things.

neutron deniers of the world unite!

Hiroshima and Nagasaki were not bombed by planes,there is no such thing as an atomic bomb,there was simply a looong tunnel dug beneath the Pacific and huge piles of dynamite (you know the black ball-shaped type with a fuse labeled BOMB) were moved and set under Japan and booom, the sun isn’t a fusion reactor,it’a just a pyre burning sinners’ fed with martian wood by angels .… oh God .…

Syntax Error: mismatched tag at line 4, column 2, byte 207 at /usr/local/lib/perl5/site_perl/5.12.3/mach/XML/Parser.pm line 187

Obviously I’m a far cry from becoming a puntiff among Parsons of the neutron-challenged fundamentalist church of particulate debris.

Oh, well.

but I have to admit I’ve never met a neutron denier before.

I’ve seen quark denial on at least one website. Don’t recall any anti-neutrons though, either.

Of course, the trouble with anti-neutrons is what happens when they happen to meet neutrons.

Henry

Thanatos said:

neutron deniers of the world unite!

Hiroshima and Nagasaki were not bombed by planes,there is no such thing as an atomic bomb,there was simply a looong tunnel dug beneath the Pacific and huge piles of dynamite (you know the black ball-shaped type with a fuse labeled BOMB) were moved and set under Japan and booom,

the sun isn’t a fusion reactor,it’a just a pyre burning sinners’ fed with martian wood by angels .… oh God .…

This explains the long running conspiracy to keep the mole-people a secret since America must have used them to beat the Japanese and keeping the Martian forests secret explains why NASA needs to keep crashing those probes. And they can’t find Noah’s ark - because it’s on Mars! It all makes sense now!

I read Parson’s crap three times looking for a point. Was there supposed to be evidence for a designer somewhere in all that useless rhetoric? Or is Parson’s so stupid he thinks that complexity can’t result from “mindless” causality? If so, he should re-read the article again, several times.

It also wouldn’t surprise me if he thinks atoms sharing electrons is more designer magic…

I was under the impression that that kind of spam was banned here.

This explains the long running conspiracy to keep the mole-people a secret

Here I disagree,there is no conspiracy to keep the mole-people secret,it’s obvious and accepted by the vast majority of people including scientists that they are all around us,they’re just very shy,

since America must have used them to beat the Japanese

it was the commander of the Legion of Free-Moles that due to long-fuse shortage stayed back and ignited the bomb,her sacrifice will never be forgotten,

and keeping the Martian forests secret explains why NASA needs to keep crashing those probes.

there was no landing on the Moon,there was no crashing on Mars,the people responsible for remote controlling a Predator-drone over Afghanistan hunting and almost getting Osama, crashed a party that day and obviously there had to be a cover-up,

And they can’t find Noah’s ark - because it’s on Mars! It all makes sense now!

elementary my dear 12th monkey.

Thanatos said:

it was the commander of the Legion of Free-Moles that due to long-fuse shortage stayed back and ignited the bomb,her sacrifice will never be forgotten,

Don’t shortchange their other heroic leader Charles Dig-Hole. OK, I need to stop. I know I need help. :-)

Here I disagree, there is no conspiracy to keep the mole-people secret, it’s obvious and accepted by the vast majority of people including scientists that they are all around us, they’re just very shy,

A bit like Hobbits, huh?

Henry

Henry J Wrote:

A bit like Hobbits, huh?

Yes but Hobbits , since the time Frodo came out as being gay , have shamefully self-exiled to New Zealand.

Basically … Parsons just used the Chewbacca defense on all of you.

Which is defined by Nancy Pelosi as: “someone asserts his claim by saying something so patently nonsensical that the listener’s brain shuts down completely.”

I somehow feel better about evolutionary theory after reading this article. The idea of vertebrates evolving from the larval stage of a sessile organism always bothered me.

The idea of vertebrates evolving from the larval stage of a sessile organism always bothered me.

The validity of a theory doesn’t depend on its conclusions not bothering people. Take the theory of evolution for example - I could list several species to which I’d really rather not be distantly related. Then there’s the theory of global warming - that one has conclusions that bother anybody that has both sense and concern for our future.

Henry

Oh it’s not the implications of the sessile organisms (as in your global warming and evolutionary theory example) so much as it seems like something like that would be an evolutionary reversal, which, to my understanding is something of a “no no”, though not impossible. It simply makes a lot more SENSE the other way. My feeling is more like phew, the data follows what is the pattern that would make the most logical sense (to me anyway).

A NEUTRON DOES NOT EXIST PER SE. It is merely a strut showing off its reversed neutral interval. If you would like to know what this ground-breaking statement means, read The Quest for Right. More info: http://questforright.com

… which no doubt includes George Carlin’s riff on contractors of the building across the street… beams and struts and conduit…

Can one of the administrator please send the creationist spammer bornagain77’s posts to the Bathroom Wall?

As usual, his post is a copy and paste quotemine.

I propose not to hold back until you earn enough amount of cash to buy goods! You should just get the home loans or just collateral loan and feel free

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This page contains a single entry by PZ Myers published on June 26, 2008 2:37 PM.

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