Nature Blog Network

Tuesday, August 28, 2007

Anemones Raise a Tentacle in Support of Evolution

Editor's note: This post was selected for publication in the anthology Open Lab 2007: The Best Science Writing on Blog.

Pachycerianthus fimbriatus from the Puget Sound raises each tentacle in support of evolution. Photo from seaotter.com.


The Anemone genome paper, that I previously had posted on, was a landmark paper in comparative phylogenomics. It provided a 'backbone' (yes, pun intended) for comparison from a supposedly more primitive state to a more derived state (i.e. arthropods, nematodes, mammals). The findings of the paper were very interesting, yet somehow they are being highly misinterpreted by certain factions, namely intelligent design "theorists". At the creationist blog, uncommon descent, there is blatant misinformation being spread about the findings. After reading the post and its comments, it is obvious that the poster and certainly the commenters have not bothered to read the paper. To really understand a scientific article one must move beyond the press releases and read the work as it stands.

As someone who has and currently is studying anemones, I would like to respond to some of the ID claims both from the original post and some of the more 'interesting' comments. I will proceed on a point by point basis:

The Waratah anemone of Australia (Actinia tenebrosa)from the Sydney Aquarium.


1) The title: Where did sea anemones get human genes? The questions is inversely phrased. It should read Where did humans get anemone genes. Or more importantly, why did humans conserve genes from the last common ancestor between an anemone and a bilaterian.

2)
Just how the heck is the Darwinian paradigm going to explain this? Advanced genetic programs installed before there was any chance of natural selection acting on them. Yikes! Another finding in the real world not predicted by, or even possible within, the Darwiniam paradigm. Another surprise for Darwinists.
Sooner or later they’ve GOT to start questioning underlying assumptions. (Naive, ain’t I?)
Yes, but for a different reason. Underlying assumptions are always tested in science. That is perhaps the penultimate reason for testing a null hypothesis. The authors of this study's underlying assumptions were certainly not that anemone's shared more in common genetically than with humans. This was an interesting surprise. Though more research is needed, the authors hypothesized that the similarity may, in part, be due to conservation of introns in human. Whereas in fly and nematode have lost not only introns, but whole genes and the links between genes. This is seen when comparing the base-pair alignments.

With regard to "advanced genetic programs installed before there was any chance of natural selection acting on them", I'm not sure what you mean by advanced. The authors described the origins of eumetazoan genes, ancient genes (i.e. predating the anemone) comprise 80% of all eumetazoan genes. Natural selection did act on the other 20% of genes to give us the fantastic animal diversity that we see today, from the cnidaria to the chordata and everything in between (including the Lophophorata Christopher!). So most of the genetic programs were evolving over millions of year prior to the last common ancestor to the cnidaria and bilateria.

Metridium senile from the New Jersey Scuba Diver


3)
Inrons[sic] again. Funny how these sections of “junk DNA” keep turning up, conserved over hundred of millions of years, with no physical expression of them for natural selection to work on.
The term 'junk DNA' is a historical term and a known misnomer to biologists. It is more readily defined as regions of the genome which no function has been identified as of yet. There are several reasons for its presence including that it is an evolutionary remnant from a time when one or several mutations rendered a coding region, insertions of transposable elements, or an unknown regulatory function. There conservation is a result of the lack of selection acting upon them. In fact in the quote above you are arguing for common descent. When genes get turned off that doesn't necessarily mean they go away. The net selective pressure purports greater exertion on physiology or morphology that is being acted on in the present, rather than reducing the genome size, which is not necessarily acted upon by external factors, i.e. no selection from the abiotic environment or biological interactions.

4)
I need not add (but will anyway, for anyone who needs it spelled out) that Darwinism has NO explanation for where these complex genes came from. How can you have a program to build complex multicellular creatures before there are any such creatures for natural selection to work on? How can you select mutations and build gene programs before there is expression of the genes? Hmmmm?
Evolutionary biologists do indeed have an explanation for the rise of complex genes, its called evolution, which coincidentally has been explaining biological phenomena for about 100 years prior to the advent of ID. The adaptations necessary to go from a single-celled organism to multicellular ones have occurred independently several times throughout evolutionary history. This is evidenced by statistically rigorous phylogenetic methods comparing single-celled protists with other multicellular eukaryotes. Hopefully someone can chime in with a reference for this. I have seen the data before but can't remember any studies and its late here... Additionally, mutations aren't selected for. An organism is not thinking that it needs a mutation so it can outrun its predator. Natural selection and indeed evolution, are reactive not proactive. We have seen evidence of rapid evolution in populations of species. For instance, snail shell thickening over 100 years with the introduction of an invasive crab is just one of many that come to mind. Snails with thicker shells survive more attacks by crabs and live longer to reproduce more often giving rise to progeny with the ability to synthesize thicker shells.

Corynactis viridis aff. off the shore of Devon from the BBC.


The following are some of the more intriguing comments:
1)
"I’m still new here, but I can’t help but ask…do people actually read the articles before declaring they falsify evolution?"
To which was replied in the next comment:
"I don’t think you fully get it. Those of us at UD (for the most part) have been following the NDEvo/creo and now NDEvo/ID debates for a long time. We are well versed in NDE and have long been making predictions of these sorts of things. Dembski and others have been doing the theoretical work which was dismissed by NDE proponents.

So when we see stories such as this, they are just more emprical findings confirming predictions of ID. We see these sorts of stories all the time. Some of them, when contested, are read thoroughly and discussed in detail. Others are just “Ok, so Darwinism is surprised again, what else is new?”

Neo-Darwinism is already falsified (in myriad ways…stick around and pay attention); new findings are fun, because they show just how “onto something” ID really is."
Was the original commenters question answered? No, therefore I will answer the question to the best of my ability. No. It is clear that the people contributing to this forum did not indeed read the actual article. Else they might have been surprised themselves to learn about the genetic evidence for the common descent of all animal phyla from the eumetazoan ancestor.

2)OK there really isn't anything else worth my effort there, I'm just wasting my time.

Pereclimenes sp. all nestled in and cozy with an anemone, ready to settle down for the night. So am I off to nestle into the cozy tentacles of my sheets and pillows (my wife would kill me if I woke her up). Good night! Sleep tight! Don't let the nematocysts bite!Photo from Acquario Marino Mediterraneo

27 comments:

  1. Advanced genetic programs installed before there was any chance of natural selection acting on them

    Okay, that one really made me toss my cookies. Before there was a chance for natural selection acting on them? What the Peyton Farquhar is this supposed to mean? Life on this planet is supposed to have appeared at least 3 billion years ago, give or take a billion. The common ancestor of cnidarians and humans probably lived around 700 million years ago, maybe a billion if you want to be really generous (not many researchers would be that generous). That gives a difference of what, two billion years at least? That's twice the amount of time since! What does the author think the microbes were supposed to be doing in all that time? Were they all really long-lived and all wearing silver rings?

    Or do they somehow think that microbes are somehow not subject to natural selection? What a great stinking mound of bull droppings that would be. Like any other organisms, microbes generally reproduce at a rate that produces more offspring than the environment can support, and so competition exists between individuals. Indeed, natural selection is usually considerably faster in microbes than in multicellular organisms, because the generation time is usually much shorter. Two seconds entering the words "bacteria" and "natural selection" into Google will prove my point, I feel.

    Hiss! Fume!

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  2. Well, I guess it's all a 'live and let live' situation here.

    This is a good post, Kevin, since by putting this sort of Q&A form of page on the internet you allow people the freedom to see that creationism isn't the only theory there is. I don't think it's something to get angry about, as the previous commenter did, as long as no god-wielding creationists don't come knocking on our castle's doors with pitchforks and torches.

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  3. Christopher, that statement really confused me. I think it was written without thinking about what it actually meant. I make that mistake too, mostly when I talk. Another argument for proofreading. I think you left me in the dust when you talked about "wearing silver rings" though...

    Here at PSU we do teach lab in intro (freshman level) Biology about natural selection for antibiotic resistence in bacteria. It is a very simple lab but teaches students (those that pay attention anyways) how introduction of a selection pressure (ampicillin) can affect the proportion of a population with the beneficial mutation. i.e. the 1% of the bacteria with the mutation for ampicillin resistance took over on plates with ampicillin in the agar. Do other universities have similar exercises in their introductory classes that allow students to do actual experiments in natural selection and see the outcome for themselves?

    Meirav, I apreciate your comments! I disagree that we shouldn't be mad, because this is calculated lies to advance a dying and scientifically empty pseudoconcept. But, we shouldn't argue angrily with them. Presenting arguments in a friendly, collegiate atmosphere is vital to the success of winning over brainwashed minds. Instead of "god-wielding creationists" knocking on our castle's doors, we have god-wielding creationists knocking on our legislative and judicial branches and knocking on our public schools doors.

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  4. I don't get it. I really don't. Even if the IDists were right that these findings countered established scientific thought, I don't see how the next logical leap is to dismiss all the work done on evolution and natural selection.

    It's like pointing to that 10th dentist and proclaiming "Ah ha! See? Chewing Trident is bad for your teeth. We should make chewing gum illegal!"

    I don't know, maybe that's a bad analogy, but it's all I've got at the moment. :) All I know is that I'm going to keep chewing gum until there someone points me to some heavily substantiated, research-backed, retested, double blind, controlled, SCIENTIFIC studies that counter the other 9 dentists. Simply saying "Because the 10th dentist told me so" ain't gonna do it.

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  5. I think you left me in the dust when you talked about "wearing silver rings" though...
    Let me corrupt your mind, then.

    LINKY!

    :P

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  6. Jim, I don't get it either. They are constantly arguing for common descent but failing to admit it! Its very frustrating as a biologist to see this uncanny, yet utterly false, logic. The analogy isn't bad... just needs a little work ;-)

    ERV, lmao. I wear a silver ring, but have at least 2 pieces of evidence against my abstinence... My silver ring though is the "affordable" rendition of the nicer gold/white gold and titanium marriage rings I already lost.

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  7. I'm very sad to head the early educational system in your country can be that easily changed; over here it's set in stone aside for the odd addition of pointless overly PC classes about the latest news or something. However, I still think kids, when coming back from school, can easily get to the internet to learn and see other things than what they're told in school. I think it'd take a long, long, LONG time before creationists will get that far.

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  8. RBH, Thanks! I am truly honored to finally get a post up on Pandas Thumb! I've actually been planning a series "Invertebrates in Support of Evolution". This might as well be #1.

    Meirav, On paper (i.e. constitution) church-state separation is set in stone regardless of what creationists say. During McCarthyism though it went to hell. I am sure it went to hell in a handbasket before then, but "under God" in the pledge of allegiance was a result of that era and I think the erosion of the church-state wall was accelerated after that.

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  9. The objections that they make to the article reminded me of their ignorance about the fact that sharks have genes for fingers, which have never been expressed. That the genes are shared by the sharks, all sharks, means that the source is in a common ancestor of the sharks, placing the genes back about 350 million years. Yet no sharks have fingers, do they? And that means that the gene doesn't get selected against, doesn't it?

    Thanks for the post, Kevin.

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  10. Kevin wrote I've actually been planning a series "Invertebrates in Support of Evolution". This might as well be #1.

    I think that's a good idea, and it will surely get you in good with PZ. He likes squishy critters, too. :)

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  11. I'm not sure we should all be so nice and calm in responding to these lunatics. I know it's the 'proper' decorum, but we're dealing with a bunch of religious nuts whose sole purpose seems to be steamrollering an obviously bogus argument (ID) for the sole purpose of enhancing their POLITICAL powers.

    I'd just as soon mock, ignore, shout down or bitchslap them as to attempt to engage in 'intelligent' debate NONSENSE with them. In other words, and as an easily understood analogy, I am also not willing to engage in a formal debate about whether water is wet.

    Enjoy.

    Wanna get a Republican Horny?
    http://www.flickr.com/photos/timtimes/1277152453/
    Worksafe and funny as hell

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  12. Nice post!
    (Pedantically, though, "penultimate" means "second-to-last")

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  13. Mike, I am sure I have genes for gills that have never been expressed...

    Anonymous, it doesn't have to do with proper decorum. I don't want to stoop down to their level and revert to name-calling. I prefer trying to convert the more thoughtful people that are on the sidelines reading these posts. The posters and ridiculous commenters are lost to science, they don't count in my book. But I know there are several people who read such threads and hopefully read threads like mine and panda's thumb and think about what they read.

    If these constituents see me going off on a angry rant (as I often do in real life) they might write me off as evolution fundie (which of course I am) and not pay attention to arguments or comments that I propose.

    From my own observations, I found it typically backfires on the angry ranter, as then opponents will nitpick on the name-calling bits and lose interest in the arguments. My life goal (1 of among several) is to persuade as many naysayers of evolution with hopefully useful bits of information related to my beloved invertebrates. If 1 get 1 person to think about all the negativity, scientific retardation, and fallacies etc. of ID then I am satisfied.

    Larry, thanks for the link! It is an honor to have one my posts appreciated by so many.

    Sven, thanks for the correction! English is my first language... I swear!

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  14. The concept of "Junk DNA" expresses the idea there are good theoretical reasons to suppose that some regions of noncoding DNA that have no current selective value, and exist in the genome purely as vestigial remnants of evolution or as "selfish DNA."

    Unfortunately, some people have taken "junk DNA" as being synonymous with "noncoding DNA," which is nonsensical. It was known even before the "junk" term was coined that important regulatory sequences reside in noncoding DNA.

    The "junk DNA" concept is more properly regarded as a null hypothesis. The mere existence of a sequence in the genome is not evidence of function; additional data is required to draw such a conclusion.

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  15. Kevin Z. & Christopher T.,

    It requires a little more familiarity with ID and creationist foolishness to parse:

    Advanced genetic programs installed before there was any chance of natural selection acting on them

    One of the stranger ideas from the anti-evolution crowd was that evidence for a designer/creator might be found in DNA that had no function in early forms, but would be sitting there waiting to be used once its descendents needed to use it.

    By ignoring that common ancestor and heaping fallacy on anthropocentric fallacy, one can come up with the idea that the genes found in the anemones are necessarily human genes and therefore 'advanced'.

    In his hypothesis, these 'human' genes might code for a brain, as an example. Since the anemone is not expressing these genes to make a brain, they are not going to be subject to natural selection.

    This is one of those hypotheses that are so bad they are not even wrong. I could make the effort to find the places I came across this drek on the web so as to provide references, but it's been a long day.

    Wonderful images, by the way. I am having a hard time picking a favourite.

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  16. Anonymous, I agree. Unfortunately its too late to do away with the phrase "junk DNA", the damage has been done. Its also unfortunate that the ID movement picks out the semantics without understanding what is really meant, or the deeper meaning.

    JohnS, with this logic then the ID/creationists must accept common descent. If our genes are lying in wait for us from a "lower" animal, then we must have descended from them in order to keep our genes. I disagree that the hypothesis is so bad they are not even wrong. The are wrong on so many levels!

    I'm a firm believer in fighting ID with beautiful pictures of anemones. Shower them with the beauty and awe of invertebrate evolution!

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  17. I apologize to any previous poster who has pointed this out (bare with me, I'll sort of negate myself in a second), but I can't help but notice that not only do commentators don't read the full work, but lack the understanding of basic biological principles. They should know better that you can't fight an enemy on his own turf without mastering his weapons.

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  18. I agree Romunov, I've read most of the bible and could quote mine it till the cows come home to prove just about any point I wanted. I WISH that ID proponents could accept that (minimally) science can't be accepted on faith. There is a specific definition of what science is. Though this definition may vary between individuals, it invariably includes that it is "a process", it is "objective", applies "empirical principles" to study natural phenomena (though some may disagree to an extent that other inferential methods are valid depending on context), and does not relegate an unknown to a supernatural cause.

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  19. An organism is thinking that it needs a mutation so it can outrun its predator.

    I assume you meant to write “is not” here.

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  20. thanks kai, I made the correction in the text. its what i get for blogging at midnight and being a lazy proofreader in general.

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  21. Great post, and an important one. I wanted to note that the plural of anemone is "anemones", not "anemone's". It's driving me crazy!

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  22. Freaking nit-picky english bastards. I hate you cause your always right!

    ReplyDelete
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