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Convergent evolution: Distantly related birds, same crests

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The second bird’s crest is result of single mutant gene/Sydney Stringer

From ScienceDaily:

A few years ago biologists found that a prominent change in pigeon plumage, head crests, could be traced to a mutation in a single gene. Now the research team has found an almost exact repeat in the evolutionary playbook in distantly related doves.

Evolutionary playbook? Doesn’t that imply a strategy? Oh wait, that’s heresy. Watch your language around Top People!

Evolutionary biologist Michael Shapiro and his team from the University of Utah made international headlines in 2013 when they found that a prominent change in pigeon plumage, head crests, could be traced to a mutation in a single gene.

Now, in the new advanced online edition of Molecular Biology and Evolution, the research team has found an almost exact repeat in the evolutionary playbook. A mutation in the same gene, EphB2, has led to a similar result in domesticated ringneck doves. The mutation causes the feathers on the back of the head and neck to grow up toward the head in a striking look.

“We know that many genes are involved in feather development, so it’s rather remarkable that the same gene appears to control the same trait in two distantly related species,” said Shapiro.

Next, armed with new DNA banks of bird species, Shapiro’s team will examine how far and wide this unique evolutionary twist may be found amongst other bird species and wild populations.

Here’s the abstract:

Head crests are important display structures in wild bird species and are also common in domesticated lineages. Many breeds of domestic rock pigeon (Columba livia) have crests of reversed occipital feathers, and this recessive trait is associated with a non-synonymous coding mutation in the intracellular kinase domain of EphB2. The domestic ringneck dove (Streptopelia risoria) also has a recessive crested morph with reversed occipital feathers, and interspecific crosses between crested doves and pigeons produce crested offspring, suggesting a similar genetic basis for this trait in both species. We therefore investigated EphB2 as a candidate for the head crest phenotype of ringneck doves and identified a non-synonymous coding mutation in the intracellular kinase domain that is significantly associated with the crested morph. This mutation is over 100 amino acid positions away from the crest mutation found in rock pigeons, yet both mutations are predicted to negatively affect function of the ATP-binding pocket. Furthermore, bacterial toxicity assays suggest that crest mutations in both species severely impact kinase activity. We conclude that head crests are associated with different mutations in the same functional domain of the same gene in two different columbid species, thereby representing striking evolutionary convergence in morphology and molecules. (paywall) – Convergent evolution of head crests in two domesticated columbids is associated with different missense mutations in EphB2. Anna I. Vickrey, Eric T. Domyan, Martin P. Horvath, and Michael D. Shapiro. Mol Biol Evol, June 23, 2015 DOI: 10.1093/molbev/msv140

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Comments
Zachriel:
Our position concerned the substantive findings of Gallant et al.
That you think there was a "substantive finding" shows how desperate your position really is.Virgil Cain
July 9, 2015
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Virgil Cain: Empirical observation is redundant. While all empiricism is based in observation, not all observation is empirical; hence we modify the term observation with the adjective empirical. We provided examples from authoritative sources. Virgil Cain: semantics is the argument Our position concerned the substantive findings of Gallant et al. Good luck with your semantic endeavors.Zachriel
July 9, 2015
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Empirical evidence, data, or knowledge, also known as sense experience, is a collective term for the knowledge or source of knowledge acquired by means of the senses, particularly by observation and experimentation.
- wikipedia Empirical observation is redundant.Virgil Cain
July 9, 2015
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Zachriel:
Still arguing semantics rather than substance.
Umm semantics is the argument, duh.
The title of the paper is “Genomic basis for the convergent evolution of electric organs”.
Titles don't do anything. And that title definitely does not say that they did what you claimed.
They did far more than speculate.
No, they didn't. Obviously you are confused.
They tested Darwin’s original hypothesis by assembling the genome of the electric eel (Electrophorus electricus) and sequencing electric organ and skeletal muscle transcriptomes from three lineages that have independently evolved electric organs. That’s not speculation. That’s called scientific research.
LoL! The speculation comes from thinking electric organs can evolve in populations that never had one. They assumed the lineages evolved their electric organs.
From the chapter you didn’t read:
We read it and it doesn't help you.
By showing the availability of a stepwise selectable pathway.
And they didn't do that. No one knows if mere muscle tissue can evolve into an electric organ. Without the experiment we mentioned they have nothing but musings and science confirms that fact.Virgil Cain
July 9, 2015
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Virgil Cain: So the fact that you posted “empirical observations” proves that you are clueless when it comes to science. Still arguing semantics rather than substance. Not all observation is empirical, hence the use of the adjective. Here's a typical example from the Encyclopedia of Philosophy, and another from the National Science Foundation:
The method was to, in the first place, explore it by empirical observation. Look, but look carefully and systematically. http://www.iep.utm.edu/desc-sci/
the research should be based on empirical observation or be subject to empirical validation or illustration http://www.nsf.gov/funding/pgm_summ.jsp?pims_id=5369
Virgil Cain: if the paper isn’t specifically about the evolution of electric organs then why did you bother baldly posting it The title of the paper is "Genomic basis for the convergent evolution of electric organs". Virgil Cain: That is all they did. They did far more than speculate. They tested Darwin's original hypothesis by assembling the genome of the electric eel (Electrophorus electricus) and sequencing electric organ and skeletal muscle transcriptomes from three lineages that have independently evolved electric organs. That's not speculation. That's called scientific research. Virgil Cain: Now we know that you are lying as Darwin was ignorant of genetics and as such could not have hypothesized a plausible pathway. Darwin didn't propose a plausible pathway, but hypothesized that a plausible pathway existed, one that was beyond his ken. From the chapter you didn't read:
Darwin: The electric organs of fishes offer another case of special difficulty; it is impossible to conceive by what steps these wondrous organs have been produced; but, as Owen and others have remarked, their intimate structure closely resembles that of common muscle; and as it has lately been shown that Rays have an organ closely analogous to the electric apparatus, and yet do not, as Matteuchi asserts, discharge any electricity, we must own that we are far too ignorant to argue that no transition of any kind is possible.
Virgil Cain: Also what, exactly, makes it “plausible”? By showing the availability of a stepwise selectable pathway.
Darwin's hypothesis: muscles evolved into the electric organ (evolved meaning selectable stepwise adaptation). Gallant et al: Shows a plausible adaptive pathway.
So Darwin predicted results only available 150 years into the future. Lucky guess?Zachriel
July 9, 2015
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Zachriel, Using "empirical" and "observation" together doesn't make any sense, given the definition of empirical. So the fact that you posted "empirical observations" proves that you are clueless when it comes to science.
To address the specifics means that your objection has to be specific to the paper itself.
Well if the paper isn't specifically about the evolution of electric organs then why did you bother baldly posting it? From the data and assuming the different electric organs did evolve from populations that did not have one, they speculated on how it might have happened. Zachriel:
They did more than speculate.
That is all they did.
They provided a plausible pathway, as hypothesized by Darwin.
Now we know that you are lying as Darwin was ignorant of genetics and as such could not have hypothesized a plausible pathway. Also what, exactly, makes it "plausible"? They have never actually tested it.Virgil Cain
July 8, 2015
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Virgil Cain: Heh. Non-responsive. Virgil Cain: Your childish misrepresentations are not an argument. That's exactly what you did. You can object to any research paper with the exact same sentence. alter VC: There isn’t any specific evidence presented in the paper that demonstrates that the Earth moves. alter VC: There isn’t any specific evidence presented in the paper that demonstrates that atoms exist. alter VC: There isn’t any specific evidence presented in the paper that demonstrates {whatever you put in here}. To address the specifics means that your objection has to be specific to the paper itself. Virgil Cain: From the data and assuming the different electric organs did evolve from populations that did not have one, they speculated on how it might have happened. They did more than speculate. They provided a plausible pathway, as hypothesized by Darwin.Zachriel
July 8, 2015
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Zachriel:
The paper is full of empirical observations.
Heh.
To be specific, you have to refer to the supporting data.
There isn't any specific evidence presented in the paper that demonstrates an electric organ can evolve in a population that never had one. From the data and assuming the different electric organs did evolve from populations that did not have one, they speculated on how it might have happened.
“Is not!” is not a specific objection.
Your childish misrepresentations are not an argument.Virgil Cain
July 8, 2015
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Virgil Cain: Only experimentation which demonstrates such a thing can support Darwin. The paper is full of empirical observations. They went to a lot of trouble to collect the data. It would be reasonable to refer to the data before waving your hands. Virgil Cain: We already told you and you have already choked on them. "Is not!" is not a specific objection. To be specific, you have to refer to the supporting data.Zachriel
July 8, 2015
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Our analysis suggests that a common regulatory network of transcription factors and developmental pathways may have been repeatedly targeted by selection in the evolution of EOs, despite their very different morphologies. Moreover, our work illuminates convergent evolution of EOs and emphasizes key signaling steps that may be foci for the evolution of tissues and organs in other organisms.
That would work if and only if it requires fewer than 3 specific mutations: Waiting for Two Mutations: With Applications to Regulatory Sequence Evolution and the Limits of Darwinian Evolution- And that means it didn't happen the way you think.Virgil Cain
July 8, 2015
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Zachriel:
Now tell us specifically why you disagree with the findings.
We already told you and you have already choked on them.
Darwin hypothesized that the electric organ evolved from muscle tissue, but had no idea how it could have happened.
And that is true today- no one has any idea if such a thing could happen.
Gallant et al. provide the how, supporting Darwin’s hypothesis.
No, they didn't. Only experimentation which demonstrates such a thing can support Darwin. Absent of that all there is is speculation based on the assumption.Virgil Cain
July 8, 2015
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Virgil Cain: The authors didn’t provide any such thing. That's your claim. Now tell us specifically why you disagree with the findings. Darwin hypothesized that the electric organ evolved from muscle tissue, but had no idea how it could have happened. Gallant et al. provide the how, supporting Darwin's hypothesis.
Our analysis suggests that a common regulatory network of transcription factors and developmental pathways may have been repeatedly targeted by selection in the evolution of EOs, despite their very different morphologies. Moreover, our work illuminates convergent evolution of EOs and emphasizes key signaling steps that may be foci for the evolution of tissues and organs in other organisms.
Zachriel
July 8, 2015
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You can’t point to any specifics that demonstrate that electric organs evolved in a population that never had one. Zachriel:
We did. The authors provided evidence of a selectable, evolutionary pathway from muscle tissue to the electric organ.
The authors didn't provide any such thing. If they had then they would have produced an experiment to confirm it. No confirming experiment means they don't have any science. No science means science doesn't care what they say.Virgil Cain
July 8, 2015
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Virgil Cain: You can’t point to any specifics that demonstrate that electric organs evolved in a population that never had one. We did. The authors provided evidence of a selectable, evolutionary pathway from muscle tissue to the electric organ.Zachriel
July 8, 2015
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Shockingly Fishy Conclusions: Evolutionary spin doctors try to explain how the electric eel, and five other groups of electric fish, evolved their electrifying characteristics independently. and Electric fish exist—there is no question of that. But their existence does not prove that they evolved. Convergent evolution is their explanation simply because they can’t explain it any other way.Virgil Cain
July 8, 2015
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Zachriel:
We asked for specifics.
And we provided them. You can’t point to any specifics that demonstrate that electric organs evolved in a population that never had one. Try reading the paper, Zachriel.Virgil Cain
July 8, 2015
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Virgil Cain: They never verified their speculations. We asked for specifics. Try reading the paper, and tell us what about the paper you find problematic.Zachriel
July 8, 2015
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Zachriel:
In other words, you can’t point to an specifics of the paper that you find problematic.
They never verified their speculations. It is incomplete. You can't point to any specifics that demonstrate that electric organs evolved in a population that never had one.Virgil Cain
July 7, 2015
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Virgil Cain: They didn’t conduct the experiment that would verify if their musings had any merit. In other words, you can't point to an specifics of the paper that you find problematic.Zachriel
July 7, 2015
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Zachriel- If they know what genes are involved then they need to conduct the experiment to see if their hypothesis has any merit. Obviously you are ignorant as to how science works.
If you have issues with the paper, please be specific.
They didn't conduct the experiment that would verify if their musings had any merit. They have no idea if an electric organ can evolve from a population that never had one. Obviously you are just a gullible chump who accepts anything it thinks supports its position.Virgil Cain
July 7, 2015
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Virgil Cain: The paper doesn’t tell us what genes were involved. You didn’t read the paper, obviously. Virgil Cain: Again if Gallant had something real then experiment would confirm it. Actually, the paper is chock-full of empirical results. If you have issues with the paper, please be specific.Zachriel
July 7, 2015
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Zachriel:
What Gallant shows is that the electric organ is just a modified muscle.
Except they didn't show any such thing. Obviously you are just a gullible chump who accepts anything it thinks supports its position. Again if Gallant had something real then experiment would confirm it. We await that experiment. Absent that please read the article linked to in comment 21Virgil Cain
July 7, 2015
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Virgil Cain: Nothing about any prediction of what electric organs evolved from. From the same chapter:
"The electric organs of fishes offer another case of special difficulty; it is impossible to conceive by what steps these wondrous organs have been produced; but, as Owen and others have remarked, their intimate structure closely resembles that of common muscle; and as it has lately been shown that Rays have an organ closely analogous to the electric apparatus, and yet do not, as Matteuchi asserts, discharge any electricity, we must own that we are far too ignorant to argue that no transition of any kind is possible."
Virgil Cain: Also Gallant doesn’t know if an electric organ can evolve in a population that never had one. What Gallant shows is that the electric organ is just a modified muscle.Zachriel
July 7, 2015
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No, reality already stepped in and refuted Darwin. Zachriel:
Darwin: The electric organs offer another and even more serious difficulty; for they occur in only about a dozen fishes, of which several are widely remote in their affinities. Generally when the same organ appears in several members of the same class, especially if in members having very different habits of life, we may attribute its presence to inheritance from a common ancestor; and its absence in some of the members to its loss through disuse or natural selection. But if the electric organs had been inherited from one ancient progenitor thus provided, we might have expected that all electric fishes would have been specially related to each other. Nor does geology at all lead to the belief that formerly most fishes had electric organs, which most of their modified descendants have lost.
Nothing about any prediction of what electric organs evolved from.
Rather, it was to find how evolution was able to adapt muscle tissue as an electric organ in widely disparate vertebrate species.
"Evolution" is a nebulous term. Perhaps you are unaware of what ID is and what it is arguing against. Also Gallant doesn't know if an electric organ can evolve in a population that never had one. All they have done is assume electric organs did evolve and then speculate as to how that may have happened. Next they need some way to test that speculation.Virgil Cain
July 6, 2015
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Virgil Cain: No, reality already stepped in and refuted Darwin. You claimed that the quote phrase above had nothing to do with electric organ. You should have been able to find the context from the citation provided, but here's the paragraph in question.
Darwin: The electric organs offer another and even more serious difficulty; for they occur in only about a dozen fishes, of which several are widely remote in their affinities. Generally when the same organ appears in several members of the same class, especially if in members having very different habits of life, we may attribute its presence to inheritance from a common ancestor; and its absence in some of the members to its loss through disuse or natural selection. But if the electric organs had been inherited from one ancient progenitor thus provided, we might have expected that all electric fishes would have been specially related to each other. Nor does geology at all lead to the belief that formerly most fishes had electric organs, which most of their modified descendants have lost. The presence of luminous organs in a few insects, belonging to different families and orders, offers a parallel case of difficulty. Other cases could be given; for instance in plants, the very curious contrivance of a mass of pollen-grains, borne on a foot-stalk with a sticky gland at the end, is the same in Orchis and Asclepias, genera almost as remote as possible amongst flowering plants. In all these cases of two very distinct species furnished with apparently the same anomalous organ, it should be observed that, although the general appearance and function of the organ may be the same, yet some fundamental difference can generally be detected. I am inclined to believe that in nearly the same way as two men have sometimes independently hit on the very same invention, so natural selection, working for the good of each being and taking advantage of analogous variations, has sometimes modified in very nearly the same manner two parts in two organic beings, which owe but little of their structure in common to inheritance from the same ancestor.
Virgil Cain: Also Gallant cannot account for that toolkit and neither can natural selection. That wasn't the purpose of the study. Rather, it was to find how evolution was able to adapt muscle tissue as an electric organ in widely disparate vertebrate species.Zachriel
July 6, 2015
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Zachriel:
Do we have to quote the entire paragraph, the entire chapter, or the entire book? Darwin, Origin of Species 1859.
No, reality already stepped in and refuted Darwin.
By determining the common toolkit that allowed for convergence, a simplified and selectable pathway.
Speculation based on the assumption. Also Gallant cannot account for that toolkit and neither can natural selection. Again if Gallant had something real then experiment would confirm it. We await that experiment. Absent that please read the article linked to in comment 21Virgil Cain
July 6, 2015
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Virgil Cain: A nebulous concept if there ever was one and nothing referring to electric organs. Do we have to quote the entire paragraph, the entire chapter, or the entire book? Darwin, Origin of Species 1859. Virgil Cain: In what way was the concept supported by Gallant seeing that Gallant doesn’t know if such a transformation is possible? By determining the common toolkit that allowed for convergence, a simplified and selectable pathway.Zachriel
July 6, 2015
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“Natural selection, working for the good of each being and taking advantage of analogous variations, has sometimes modified in very nearly the same manner two parts in two organic beings.” — Darwin
A nebulous concept if there ever was one and nothing referring to electric organs.
Specifically, Darwin posited that electric organs evolved from muscle tissue, as supported by Gallant et al.
In what way was the concept supported by Gallant seeing that Gallant doesn't know if such a transformation is possible?Virgil Cain
July 6, 2015
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Virgil Cain: What are the entailments of natural selection and/ or drift producing electric organs. “Natural selection, working for the good of each being and taking advantage of analogous variations, has sometimes modified in very nearly the same manner two parts in two organic beings.” — Darwin Specifically, Darwin posited that electric organs evolved from muscle tissue, as supported by Gallant et al.Zachriel
July 6, 2015
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Zachriel:
“Blind watchmaker” is an analogy, not a scientific concept.
"Blind watchmaker" refers to natural selection, which is a failed analogy to artificial selection. Are you saying tat natural selection is not a scientific concept? What are the entailments of natural selection and/ or drift producing electric organs. YOU brought up entailments now either you can post what those are or you can continue with your nebulous claims.
But if you want details of how the electric organ evolved, try reading Gallant et al.
They only have speculation based on the assumption. If they had something real then they should be able to demonstrate it experimentally. If we want science with details then we wouldn't recommend evolutionism. Einstein had some very specific predictions from his equations but evolutionism doesn't have anything close to that.Virgil Cain
July 6, 2015
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