8/25/2007

VOX DEI BATE #8: PUTTING 'TENS' TO THE TEST



The above link shows the irreppresible Ken Miller in action. I want to mention that up-front, because I am deeply indebted to Dr. Miller on a number of levels. A celebrated advocate for evolution who testified for the plaintiffs in the Dover trial, he is also the author of one of the widely-used high-school textbooks in North America, Prentice-Hall Biology. Dr. Miller has graciously allowed me to use his work on more than one occasion, including in the preparation of this post. Details and acknowledgments below.*

In the previous post, I claimed that I was going to present a clear example of an independent test of morphological change being the result of evolution, and the sort of change that clearly supports an inference of common descent between two different species. The example I’ve chosen, the alleged descent with modification of modern chimpanzees and humans from a common ancestor, is just such an example. Because of their prior commitments, almost all creationists are going to feel compelled to admit that this case, if true, is a demonstration of ‘macroevolution.’ I can’t imagine any creationist who wouldn’t admit that the gap between chimps and ourselves is anything other than a large-scale event, since they seem to be at pains to deny anything that compromises the privileged status of a certain primate species.**

So this is a good way to test the 'slippery slope' of 'macroevolution', since when you try to pin some creationists down, they'll admit some changes occurs, even speciation events----but they'll shift the playing field, saying that your example, whatever it was, is not really 'macroevolution' but simply variation within the kind. Even better, this example allows us to address the claim that evolutionary theory is not predictive in a very specific way!

But I'll let Dr. Miller summarize the case. He certainly explains it far better than I ever could:

"As most of you know, there is substantial evidence that our species shares a common ancestor with the great apes –– the gorilla, orangutan and chimpanzee. But can we be sure of this? Can we put that evidence to the test? Today, we can indeed. The complete DNA sequence of one of those great apes, the chimpanzee, was published less than a week ago, and it provides us with a remarkable new opportunity to answer a question that has fascinated people of every culture, of every place and time. Where did we come from?

We human beings carry our genetic information on 23 pairs of DNA-containing chromosomes. The great ape species, on the other hand, have 24 pairs. And there’s the mystery. How could we share a common ancestor with them if you and I and even President Simmons are, quite literally, missing a chromosome? Where’d it go?

Well, if one thought that our genome was "designed," as many Americans seem to, it wouldn’t have gone anywhere. If our DNA was the unique product of an intelligent designer, that fellow could simply have arranged our DNA in fewer packages than the apes, and since there is no real relationship between us and them, nothing would be missing.

But if a fellow named Charles Darwin was right, there is a relationship, a link, and the remnants of that missing chromosome have to be somewhere inside us. You couldn’t just throw a whole chromosome away, and therefore evolution makes a testable prediction. When we lay the human and chimpanzee genomes side by side, we’ve got to find a human chromosome constructed by sticking two chromosomes together from that common ancestor. And if we cannot find it, evolution is wrong. Well, guess what? It’’s chromosome #2.


Our second chromosome was produced by the head to head fusion of ape chromosomes 12 and 13, and the new primate and human data show the exact point at which those two chromosomes were pasted together. No doubt about it –– like a criminal at the scene of a crime, evolution left its messy fingerprints all over us –– and we know where we came from. Like everything else on this planet, we evolved.

Whether you find that conclusion depressing or exhilarating, it changes the way we see our world, our existence, and our relationship to every other living thing that inhabits this planet. It’s practical knowledge, to be sure, but like all true knowledge, it has the power to change, enlighten, and transform."

I can't add much more than that, other than a caution. This example powerfully demonstrates macroevolution, and that the application of TENS to a particular problem (such as the question of our relationship to other primates) yields testable predictions. There is a plausible series of natural events which can account for the genetic and morphological differences between human beings. What it does not demonstrate, however, is that in this particular case all of the evolution we see is entirely due to natural selection alone. But (and this bears repeating) contemporary biology makes no such claim, and those who say that we do are putting forth a 'straw man' to justify their skepticism of evolutionary theory in general. If things were as such critics claim, then the textbooks would not include things like genetic drift or endosymbiosis.

Now, I think this observation has some bearing on some issues that Vox has raised in the past few posts as to how some 'evolutionists' have enlisted Darwin to 'attack religious faith', ridicule politicians who fail to say they 'believe in evolution', or attempt to suppress skepticism about TENS as unscientific. I will try to address these in a future post. For now, I will simply tackle his most recent question for me:

"...if many other complex models which backtested better than TENS have proven to be roundly unsuccessful when their future predictions have been subjected to rigorous scientific experimentation, what is the basis of your apparent belief that TENS-based models will prove more successful?"

I'm not sure this is a meaningful question for me, for two reasons: first, because I don't have a commitment one way or the other against any future model; second, because it's the wrong way to conceptualize the matter, that things will either be TENS-based or not. Here's what I would say: evolution and natural selection are both facts, and in particular cases a relationship between these two facts has been demonstrated, while in general cases it is inferred on the basis of multiple lines of evidence. Any future alternative to the present model will have to account for all the facts currently in our possession, and among those facts are evolution, and natural selection.

* The video is an excerpt from a presentation that Dr. Miller gave at Case Western University in February of 2006, less than two months after Judge John Jones III ruled against the Dover school board. It's highly similar to a talk that I saw Dr. Miller give a few months later in Modesto, California. The illustrations in this post are adapted, with Dr. Miller's permission, from the Power Point that he used in both talks, a copy of which is available here both as a presentation and a PDF file from the AAAS. Dr. Miller has also consented to my sharing excerpts from his commencement address to Brown University students in September 2005, which summarizes the findings under discussion in a concise and user-friendly fashion.

** It should not be inferred that the latter is Vox’s position, or that he will either endorse or reject this particular example. I am very much interested, though, in his response.

17 comments:

Starwind said...

Scott, a couple clarifying questions if you would/could?

How is the date of the fusion event determined? I’ve seen assertions/estimates of anywhere from several mya to less than one mya. What is the “date evidence” and how is it interpreted?

Why didn’t the fusion event result in unviable offspring or genetic diseases? Aren’t such chromosomal differences ('fused' 46-chromo individuals vs pre-fused 48-chromo individuals) normally reproductively isolating? How did the reproductive individuals with these “fusions” arise and mature cotemporaneously and produce viable offspring?

There are other strong homologies between human and chimp chromosomes. Why the emphasis on the fusion of chromosome 2 and not, for example, on the near identical banding patterns of chromosome 3 and the inverted segment in chromsome 4? Why is this fusion believed to be so much more significant evidence of TENS than other existing homologies?

Richard said...

Scott --
Vox is quite enamored of his example:

...I'll demonstrate why by mentioning the validation of an even more astounding "prediction" which was made 2,600 years ago. The Book of Jeremiah claims in chapter 39 verse 3 that an officer named Nebo-Sarsekim was with the Babylonian King Nebuchanezzar II at the siege of Jerusalem...

by concluding:

One cannot reasonably argue that one prediction of subsequently confirmed past events is proper science while the other is not. If we must accept TENS on the basis of an aquatic bear skeleton, then we must also accept the Bible, (or at least the Book of Jeremiah, including the bits about the Lord speaking to him) - frankly, the Biblical "prediction" is much more impressive, being more than 20 times older - and I doubt many scientists are inclined to accept that conclusion...

but Vox is conveniently leaving out a contradicting fact:


...Spelling variations may seem like a minor problem, but they highlight a greater issue, namely the inconsistency between archaeological evidence and biblical text. One notorious discrepancy involves the 701 B.C. Babylonian campaign against Jerusalem. According to the Bible, Sennacherib, the Babylonian king who reigned from 701-681 B.C., was unsuccessful in his attempt to sack the city of Jerusalem. The Old Testament states that an angel came during the night to kill 185,000 soldiers, forcing Sennacherib and his weakened army to retreat (II Kings 18-19).

King Sennacherib, however, left a conflicting report on an artifact now known as the Prism of Sennacherib. Standing 38 cm high, the hexagonal clay prism contains 500 lines of writing on six columns. In direct opposition to the Bible, it states that Sennacherib captured settlements belonging to the King of Judah, took the king's daughters and enforced a heavy tribute. Both historical accounts cannot be completely correct, but in the absence of further archaeological evidence, historians can only speculate about what actually occurred...

(taken from) http://www.archaeology.org/online/features/jeremiah

Unlike Vox's "prediction" there are no known exceptions to speciation so far the fossil record. You note that we cannot know if species A is the direct ancestor of B leading to C, but this is not essential -- induction allows us to feel confident that as long as C cannot suddenly come before A the gaps are not essential. What alternatives have we? That all A died out, then B suddenly sprung forth, fully formed? (B had no parents, but amazingly was created with attributes 99% in agreement with the now extinct A?) Or perhaps after B died out, C arrived from another planet?

All scientific induction is based upon this logic, and while not as strict as mathematical induction, it has worked very well in every area from physics to chemistry and evolution.

If an exception is found, evolutionary science will be forced to adapt it's theories (the simultaneous strength and weakness of the scientific method). Is Vox prepared to adapt this theory that the bible is infallible?

And as Vox is preparing his defense of how TENS is unscientific, it would behoove him to note this quote from Isaac Asimov:

[W]hen people thought the Earth was flat, they were wrong. When people thought the Earth was spherical they were wrong. But if you think that thinking the Earth is spherical is just as wrong as thinking the Earth is flat, then your view is wronger than both of them put together.

Scott Hatfield . . . said...

Starwind:

Good questions.

#1 (date of fusion event) I'll have to research that, because I'm not sure if the 'fusion event' is being treated separately here from previous studies that estimate the date of the LCA on morphological or molecular grounds. I suspect not, in which case the dates assigned are based upon existing models of the later data. But I will get back to you on that.

2# (Deleterious results of fusion event) Fusion events happen all the time. Because they are radical reorganizations of the genome, we would expect reproductive problems to arise, and for these to normally be evolutionary dead-ends. However, a fusion event that did not lead to such problems would only need to have occurred once, so it can't be eliminated on probability grounds. We should be very honest and admit that we do not understand these events very well: how could we, when most such examples have only recently been discovered via comparative genomics?

#3 (homologies) It has to do with the fact that we have a specific prediction that would've been trivially easy to falsify, confirmed to a precision of 15 base pairs, and a prediction that really excludes supernatural intervention from any God that would not be attempting to deceive us.

After all (to play the devil's advocate), banding patterns could simply reflect a common design from a common designer. The inverted segment you refer to could've been the creator flipping one of the modules in the 'design'...

But, to find two telomeres within chromosome #2, and a deactivated centromere region? The only way to retain a role for deity here is to say the good Lord fiddled with the existing variation of an individual who was part of a lineage shared with other primates, and fiddled with it in such a way as to make all of the changes appear entirely natural.

Scott Hatfield . . . said...

Richard: Naturally, I concur.

jack said...

Can fusion happen naturally? Can the statement that it can be or has happened naturally be proven? Citations please.

I knew of the fact that the human genome has fused chromosomes. I once read somewhere that this can only be done in a genetics lab [or by the Creator, if you will]

Curious on your take.

Scott Hatfield . . . said...

Jack:

Wholesale deletions, duplications, inversions and translocation of chunks of chromosome happen all the time--naturally. In fact, at any given moment, there are cells in the very act of division within our own bodies which are experiencing chromosomal mutations, and this fact can be gleaned from most high school biology texts.

Some combination of the above could lead to the necessary conditions for a fusion event described in this thread. These are less common, but as to their relative frequency or the likelihood of said event being favored by selection, I can't say off-hand. It's not my field. If you like, I'll look into that for you.

In the meantime, please consider reading Sean Carroll's book 'The Making of the Species', because it will probably address the topic better than I can.

The likelihood of such

Starwind said...

Scott hatfield:
However, a fusion event that did not lead to such problems would only need to have occurred once, so it can't be eliminated on probability grounds. We should be very honest and admit that we do not understand these events very well:

I wans't arguing its elimination. I was questioning its probability (and indirectly its "predictability" as per TENS). Obviously, based on outcome the fusion of HSA2 wasn't species-ending. But HSA2 does carry a huge amount of genetic diseases and one can question to what extent the fusion:
a) improved/degraded homosapiens
b) occured before/after emergence of the genus (many cytlogists regard the HSA2 fusion as speciation within homospaiens and not establishing the homo genus, right?)

Also, to further clarify my question, when you write "only need to have occurred once", by "once" do you mean a single event of fusion, or do you mean survival of a reproductivly mature individual, or survival of a reproductivly mature offspring? or pairs of each the above?

It would seem several serendipitously mutual outcomes need occur to viably establish the new trait in population numbers.

Thanks for the other pending answers as well...

Scott Hatfield . . . said...

But HSA2 does carry a huge amount of genetic diseases and one can question to what extent the fusion:
a) improved/degraded homosapiens


I’m not sure that’s a meaningful observation. ‘Improved/degraded’ relative to what? Fitness is situation-dependent. Obviously, our lineage survived and all other lineages went extinct. In that sense, we are the fittest in the traditional (if misrepresented) sense of a tautology. Whatever we might have lost or gained at the fusion event, all that matters is that we share common descent with those who survived it. In a sense, we all come from a long line of ‘winners.’

b) occured before/after emergence of the genus (many cytlogists regard the HSA2 fusion as speciation within homospaiens and not establishing the homo genus, right?)

Starwind, ‘genus’ and ‘species’ are arbitrary categories which different specialists attempt to make more rigorous through various analytical techniques. ‘Speciation within homo sapiens’? But homo sapiens is the species. Perhaps you’re hoping you can recharacterize it as variation within Homo? Hey, knock yourself out if that floats your boat, but when exactly the fusion event occurred and how it relates to the emergence of Homo are technical questions that do not change the fundamental fact: a fusion event occurred since the last common ancestor with chimpanzees, and it carries the detailed signature of chromosomes not fused in the chimpanzee lineage.

Also, to further clarify my question, when you write "only need to have occurred once", by "once" do you mean a single event of fusion, or do you mean survival of a reproductivly mature individual, or survival of a reproductivly mature offspring? or pairs of each the above?

Actually, all I meant was whatever sequence of events that was needed to get from the LCA of those primates that had 48 chromosomes and those (like ourselves) had only 46.

It would seem several serendipitously mutual outcomes need occur to viably establish the new trait in population numbers.

That would only be true if one assumed that all of the genome reorganization had to happen at once. If the fusion event was preceded by events of chromosome duplication, a sort of ‘scaffolding’ would be in place that would facilitate the gradual optimization of the chromosome, in the process turning various genes ‘on’ and ‘off’. While I am unaware of any evidence that would yet support such a scenario in our lineage, you should know that chromosome duplications in the history of life are really rather common and have been shown in more than one case to have facilitated dramatic morphological changes.

I admire your rigor, but I have to wonder if all this effort is misplaced. You seem to be kicking the tires right now, as if you know the car looks good and seems to run OK, but the whole package seems too good to be true. Like the car salesman hoping to close the deal, I have to ask, 'What would it take for you to drive away in this car today?'

Starwind said...

Scott Hatfield:

I’m not sure that’s a meaningful observation. ‘Improved/degraded’ relative to what?

Relative to what has high or low selectivity. Natural selection purports to select changes which have a high probability of improved survival.

Whatever we might have lost or gained at the fusion event, all that matters is that we share common descent with those who survived it.

The premises in there are several: 1) that TENS will work in any/all possible planetary histories/futures (but the only historical test is the one we know) 2) life originated accidentally and evolved accidentally (unconfirmed) 3) that we are increasingly fit (are we stronger? healthier? smarter? or just technologically more buffered 4) that selective pressures are applied equally (for example, we haven't yet had to survive a meteor strike, and it isn't clear we are surviving HIV or H5N1).

‘Speciation within homo sapiens’? But homo sapiens is the species. Perhaps you’re hoping you can recharacterize it as variation within Homo?

"Homo sapiens sapiens" is our current taxa, ostensibly preceded by "Homo sapiens idaltu", both subspecies within the species "homo sapiens", yes? And isn't the argument that the fusion of HSA2 is an macro-evolutionary step in our "shared lineage" and does that not beg the question, ok then, what exactly is the factual evidence that the fusion of HSA2 is macro-evolution as opposed to micro-evolution or speciation (further refinement or distinction within a species)?

If the claim is the evidence is supportive of macro-evolution, then the evidence should show some species of the genus homo which lacked HSA2, some subsequent species which have it, and conclusive proof that the sole means of acquiring HSA2 was from another genus.

but when exactly the fusion event occurred and how it relates to the emergence of Homo are technical questions that do not change the fundamental fact: a fusion event occurred since the last common ancestor with chimpanzees, and it carries the detailed signature of chromosomes not fused in the chimpanzee lineage.

Yes, the evidence for the HSA2 fusion is unarguable (and wasn't being argued). What is questioned is the premise that those chromosomes could only have been inherited from a common ancestor (as opposed to many families or orders having had a common complement of chromosomes to begin with). Almost all researchers on this subject are rigorously careful to state they "infer" a history, rather than demonstrate it. They seem less certain than you.

Personally, I'd like to see the "date evidence" before I draw conclusions about what it does or does not change.

If the fusion event was preceded by events of chromosome duplication,

Do you mean like when HSA21 is duplicated (leading to downs syndrome) or are you asserting that genus homo lacked 2P and 2Q chromsomes and they had to first be duplicated in another transistional species, or other?

I admire your rigor, but I have to wonder if all this effort is misplaced.

Such rigor is required in other scientific and engineering disciplines. It has stood me well in avoiding otherwise expensive mistakes. It is slow and plodding, agreed, but it is highly reliable.

Consider the consequences of a biologist misconstruing (albeit inadvertently) the facts of evolution. Now consider the consequences of a aerospace engineer misconstruing (albeit inadvertently) the lift capacity of his deisgn.

If you're not being rigourous, mightn't it be because you don't have sufficient concern for the consequences of mistakes? If your rationale is that teaching biology doesn't require the rigor of building commercial airplanes, then consider whose rigor is likely to assure a correct result, maybe even one that can predict the next change in a disease like H5N1.

Scott Hatfield . . . said...

Starwind:

The premises in there are several: 1) that TENS will work in any/all possible planetary histories/futures (but the only historical test is the one we know) 2) life originated accidentally and evolved accidentally (unconfirmed) 3) that we are increasingly fit (are we stronger? healthier? smarter? or just technologically more buffered 4) that selective pressures are applied equally (for example, we haven't yet had to survive a meteor strike, and it isn't clear we are surviving HIV or H5N1).

I don't have time to respond to everything you wrote right at this moment, but I can state categorically that none of the above premises are implied, in any way.

I am only addressing the brute fact of our lineage's survival, a lineage which carries a conspicuous 'scar of evolution' when read with the right genetic tools.

That's it: the future performance of evolutionary models, the question of whether abiogenesis occurred, the relative roles of randomness and selection and the relative uniformity of selection pressures in a given lineage are all interesting questions, but they are not relevant. Period.

And I might add, that my comment on rigor is based not on the lack of desirability for rigor, but for where you're placing your bets. You've given me the impression that you're interested in establishing a plausible basis for skepticism where 'macroevolution' is concerned. I ask your pardon if that isn't where you're going with all this, but if it is where you're going, I'm baffled by your approach.

After all, the line that led to modern humans changed genetically in a striking way that, by your own admission, reveals common descent---if not with chimps, then from (in your words) 'many families or orders having had a common complement of chromosomes to begin with.' How can this possibly be taken as a talking point against macroevolution? You've not only given away the farm, you've deeded me all the adjoining historic buildings that were there before the farm.

Andrew said...

If the fusion event was preceded by events of chromosome duplication, a sort of ‘scaffolding’ would be in place that would facilitate the gradual optimization of the chromosome, in the process turning various genes ‘on’ and ‘off’.
I don't think there's any need of such a hypothesis. A fusion would leave cells with the same number of copies of each gene; there'd be no need to change gene expression. I would think the real problem would be in meiosis in individuals heterozygous for the fused chromosome. So long as the gametes receive either the fused chromosome, or the two source chromosomes, all should be well. But any other combination probably would not result in a viable zygote.

Starwind said...

... but they are not relevant. Period.

Unknowns are rarely irrelevant, especially when they are boundary conditions, but I guess your mileage varies.

You've given me the impression that you're interested in establishing a plausible basis for skepticism where 'macroevolution' is concerned.

I am. I'm also willing to be skeptical of any insufficiently substantiated ID, YEC or super string theories.

I'm baffled by your approach.

It is quite simply, rigorously, to separate fact from inference, premise, extrapolation etc. That doesn't mean to ignore them, but it does mean that they not be equal or overweighted to the facts.

How can ['many families or orders having had a common complement of chromosomes to begin with.'] possibly be taken as a talking point against macroevolution?

Because it was stated as opposed to common descent from a common ancestor - is that not what macro-evolution asserts?

The distinction is in what they possibly independently began with as opposed to what they possibly acquired from predecessors.

You said earlier;
I am only addressing the brute fact of our lineage's survival, a lineage which carries a conspicuous 'scar of evolution' when read with the right genetic tools.

I'm only attempting to look over your shoulder and read for myself whatever it is that you're reading, and ensure that I understand (whether you do or not) the limitations of the tools and the predispositions of the user.

I have predispositions as well. But I know mine, whereas it takes some effort to identify and weigh the predispositions of others.

I'll not belabor these further.

I would still like to see whatever "date evidence" you have for the HSA2 fusion event, if/when convenient or possible.

plunge said...

This still just seems pointless. I don't even see that Vox has laid out ANY circumstances by which he'd agree that we have convergent evidence of anything.

His claims of backtesting are so confused about the basic issue, and he seems so unwilling to reconsider them, that I don't really see a way forward with him.

I mean, he really seems to think that "testable" in science is a requirement to REPLAY HISTORY, instead of what it actually means: testing a theory against the evidence. Things like chromosomal fusions are compelling because they are entirely unexpected and otherwise unnecessary details which provide checks on the theory. There is no reason why such things should be unless common ancestry is involved. The basics of human and chimp genes do not HAVE to be thus: they very easily could have been completely incompatible with common descent.

But time and time and time again, every piece of available evidence fits into the this larger framework and does NOT disconfirm it, as it very very easily could.

Anonymous said...

This is very impressive, Scott. I don't think anyone here or there has a valid critique of it.

Genetic science always has the most interesting stuff in evolutionary theory discussions. I think that is due to its experimental focus and technological applications.

The downside is that explaining evolution in terms of genetic science is kind of like explaining auto manufacturing in terms of quantum physics:

1) Most people can't understand it well enough to evaluate your argument. This doesn't really matter as long as those people are on the outside.

2) The reductive explanation doesn't pertain to how the large-scale process "actually" happened, but rather to how it "could have" happened. I know this doesn't really matter in science, but most people believe it matters in life, so it is a stumbling block.

--emerod

Scott Hatfield . . . said...

Starwind:

Perhaps I'm misreading you, but whether or not the fusion event took place between the LCA of chimps and humans, or between the LCA of all anthropoids, or between the LCA of all primates, etc. etc. has no bearing on the question of common descent. You are misled if you think that pushing back the timing of the LCA somehow rules out the general principle of common descent. It would only rule out a recent common ancestor for chimps and humans, a conclusion that (as I mentioned) is unlikely to be accepted based on the molecular data.

Also, in an earlier post you suggested that trisomy-21 was the result of chromosome duplication. To the best of my knowledge, trisomy-21 is usually due to non-disjunction during meiois.

I would myself love to see how well the timing of this fusion event lines up with independent calibrations based upon morphology, the fossil record and (most especially) 'molecular clocks'. I appreciate the sincerity of your approach and I would enjoy further correspondence on this topic. But this thread is about to become cumbersome, as I post all the time, and I think it might be more productive via email at this point.

You can drop me a line at:

epigene13@gmail.com

Looking forward to it...SH

Starwind said...

Scott Hatfield:
but whether or not the fusion event took place between the LCA of chimps and humans, or between the LCA of all anthropoids, or between the LCA of all primates, etc. etc. has no bearing on the question of common descent.

It is precisely that tendancy to dismiss out of hand factual evidence before it is evaluated and given commensurate weight that predisposes inferences which in turn predisposes conclusions.

It would only rule out a recent common ancestor for chimps and humans,

Or it may expose an inconsistency in the phylogenetic tree perhaps better explained by some form of endosymbiosis or lateral gene transfer (see Horizontal Gene Transfer: Evidence and Possible Consequences and Ancient Horizontal Gene Transfer) which potentially could preclude some vertical inheritances (macro-evolution) from reproductive ancestors. The point being rather than dismiss the evidence, whatever it is, see where it fits best with all known evidence and inconsistencies.

in an earlier post you suggested that trisomy-21 was the result of chromosome duplication.

More precisely, I asked if that was an example of "duplication" to which you were referring.

I would myself love to see how well the timing of this fusion event lines up with independent calibrations based upon morphology, the fossil record and (most especially) 'molecular clocks'.

In case you weren't aware, there are considerable problems with "molecular clock" theory. See The origin and diversification of eukaryotes: problems with molecular phylogenetics and molecular clock estimation

I will email you.

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