Is the Human Brain a Null Hypothesis for Darwinian Evolution?

[Loudmouth]

Found an interesting paper on human brain evolution and the possible role of DUF1220 copy number. They argue that the expansion of the number of genes with the DUF1220 protein domain is strongly correlated with brain size and intelligence. Here is a snapshot of one of the figures:

https://www.researchgate.net/profil..._expansion/links/543be4550cf24a6ddb97b9e9.pdf

Gene duplication may play a more important role than substitution or indel mutations.

 

[Papias]

Gene duplication may play a more important role than substitution or indel mutations.

Uh-oh. mark is allergic to gene duplication - perhaps because it destroys the "no new information" creationist line. I'd expect a negative reaction. Or a hanky, at least. Probably not a realization that gene duplication is a common way to add new information to a genome.

Papias

 

[Loudmouth]

Uh-oh. mark is allergic to gene duplication - perhaps because it destroys the "no new information" creationist line. I'd expect a negative reaction. Or a hanky, at least. Probably not a realization that gene duplication is a common way to add new information to a genome.

Papias

Such arguments result in the creationist arguing themselves out of the conversation. If they define "new information" in such a way that evolution does not need to produce "new information" in order to produce the biodiversity we see today, then what good is it?

One of the analogies I have used before has to do with hitting a home run in baseball. You can define a home run as hitting a baseball 3,000 feet, if you want. In reality, all you have to do is hit it over the fence that is just a few hundred feet away. In reality, evolution only needs to produce the genetic differences seen between species. If those differences don't add up to new information, then evolution doesn't need to produce new information.

 

[expos4ever]

Funny that the scientists weren't aware of all this, whereas you, a lay person, on the sidelines, were, don't you think?

This is precisely the problem. I am astonished whenever some layperson claims to have undermined an argument endorsed by thousands of trained experts

While it is theoretically possible that a layperson could accomplish such a coup, it is, of course, exceedingly unlikely.

 

[USincognito]

I've been asking Mark for a decade if he's contacted the people responsible for the HAR1 study to tell them they found the silver bullet that killed human evolution. To my knowledge, all he's done is post the same OP and followups here as if no one ever addressed his opinions on the subject.

 

[Hoghead1]

This is precisely the problem. I am astonished whenever some layperson claims to have undermined an argument endorsed by thousands of trained experts

While it is theoretically possible that a layperson could accomplish such a coup, it is, of course, exceedingly unlikely.

It would appear that some laity have overdeveloped egos and underdeveloped intelligence.

 

[Papias]

Funny that the scientists weren't aware of all this, whereas you, a lay person, on the sidelines, were, don't you think?

Dunning-Kruger.

It's a recognized phenomenon that those most incompetent rate themselves significantly higher because they are too incompetent to recognize the competence of the experts.

https://en.wikipedia.org/wiki/Dunning–Kruger_effect

In Christ-

Papias

 

[PsychoSarah]

Your still splitting semantical hairs. The only way it's going to be functional is if the substitution results in a viable protein which has to get past functional constraints. Sure it happens, even in human protein coding genes but the deleterious effects far outweigh any possible, let alone imagined, adaptive evolutionary giant leaps. So far I have just laid a little groundwork with comparisons and the likelihood of these presumed adaptive changes.

Here is the actual problem:

Big Brains Require an Explanation.

About 2mya the nearly threefold expansion of the human brain from that of apes happens almost over night. Really not seeing a lot of cause and effect explanations, just a lot of speculative scenarios and of course the molecular basis is completely unknown.

Have a nice day
Mark

Actually, complete removals of genes can be extremely beneficial. Can you imagine the damage if we still retained functional gill formation genes, but none of those for the internal structures that made them work properly?

 

[Hoghead1]

Actually, complete removals of genes can be extremely beneficial. Can you imagine the damage if we still retained functional gill formation genes, but none of those for the internal structures that made them work properly?

Yes, but the fetus does develop gills, right?

 

[PsychoSarah]

Yes, but the fetus does develop gills, right?

Nope, just folds where gills would develop, and another mechanism removes them.

 

[Hoghead1]

Nope, just folds where gills would develop, and another mechanism removes them.

Doesn't that suggest to you that Haeckel; is right, that the development of the fetus recapitulates the history of evolution?

 

[Loudmouth]

Doesn't that suggest to you that Haeckel; is right, that the development of the fetus recapitulates the history of evolution?

Since humans don't develop gills, that would seem to be a problem for Haeckel. However, it is correct to say that Ontogeny evidences Phylogeny, even if it doesn't recapitulate it. The arrangement of the tetrapod recurrent laryngeal nerve is a good example of this.

 

[Hoghead1]

Since humans don't develop gills, that would seem to be a problem for Haeckel. However, it is correct to say that Ontogeny evidences Phylogeny, even if it doesn't recapitulate it. The arrangement of the tetrapod recurrent laryngeal nerve is a good example of this.

No, I don't think it was. He was simply arguing that the fetus recapitulates the history of evolution.

 

[PsychoSarah]

Doesn't that suggest to you that Haeckel; is right, that the development of the fetus recapitulates the history of evolution?

To an extent, it does, via looking at observations of actual fetuses. For example, that there is webbing between the digits of human fetuses for a period of time, and for a brief moment, developing birds have teeth. His basic idea was pretty much right, despite the flawed way he reached it. Like getting the answer of a math problem right, even though you didn't solve the equation in any valid way and pretty much just got lucky with the answer. In terms of looking at human fetuses, anyways, I think he did get to see ones from other animals. However, these "precursor" structures never develop as far as the functional versions, and are broken down.

 

[Hoghead1]

To an extent, it does, via looking at observations of actual fetuses. For example, that there is webbing between the digits of human fetuses for a period of time, and for a brief moment, developing birds have teeth. His basic idea was pretty much right, despite the flawed way he reached it. Like getting the answer of a math problem right, even though you didn't solve the equation in any valid way and pretty much just got lucky with the answer. In terms of looking at human fetuses, anyways, I think he did get to see ones from other animals. However, these "precursor" structures never develop as far as the functional versions, and are broken down.

What do you see as flawed about the way Haeckel worked? He went to a lot of trouble to obtain actual fetuses of humans and animals and compare them. His woodcut diagrams compare very well with modern photography of the fetus.

 

[PsychoSarah]

What do you see as flawed about the way Haeckel worked? He went to a lot of trouble to obtain actual fetuses of humans and animals and compare them. His woodcut diagrams compare very well with modern photography of the fetus.

He made and published some of the diagrams before getting the fetuses in some cases, making those diagrams speculative. Don't know why you are bothering to bring him up, though.

 

[Hoghead1]

He made and published some of the diagrams before getting the fetuses in some cases, making those diagrams speculative. Don't know why you are bothering to bring him up, though.

Well, we were discussing the fetus, I think. Also, creation-science people were the ones who bought Haeckel out of retirement. They claimed he fakes his data, was fired, and that there is no comparison between the faked fetuses and real ones. They used this as an attack against evolution. The truth is, none of these charges are true. I have no idea where you got the idea that he did the diagrams before he had the specimens. There is no indication of that in the historical record. Probably just another example of creation-science propaganda.

 

[USincognito]

Well, we were discussing the fetus, I think. Also, creation-science people were the ones who bought Haeckel out of retirement. They claimed he fakes his data, was fired, and that there is no comparison between the faked fetuses and real ones. They used this as an attack against evolution. The truth is, none of these charges are true. I have no idea where you got the idea that he did the diagrams before he had the specimens. There is no indication of that in the historical record. Probably just another example of creation-science propaganda.

You might find this rehabilitation, if not outright vindication of Haeckel interesting.
http://home.uchicago.edu/~rjr6/articles/Haeckel--fraud not proven.pdf

 

[Hoghead1]

You might find this rehabilitation, if not outright vindication of Haeckel interesting.
http://home.uchicago.edu/~rjr6/articles/Haeckel--fraud not proven.pdf

Yes, thanks. I think I've already been there, but I will check again.

 

[mark kennedy]

No, I don't think it was. He was simply arguing that the fetus recapitulates the history of evolution.

Recapitulation is one of Darwin's old tricks, it doesn't stand up to close scrutiny:

The so-called gill slits of a human embryo have nothing to do with gills, and the human embryo does not pass through a fish stage or any other evolutionary stage. The development of the human embryo reveals steady progress toward a fully functional human body. Never in the course of development does a human embryo absorb oxygen from water as fish do with gills. (The human embryo is fully supplied with oxygen through the umbilical cord.) In fact, these “gill slits” are not even slits. Something Fishy About Gill Slits!​

Amazing how many of these arguments are just begging the question of proof. Creationists have had answers to these arguments for years.

Found an interesting paper on human brain evolution and the possible role of DUF1220 copy number. They argue that the expansion of the number of genes with the DUF1220 protein domain is strongly correlated with brain size and intelligence. Here is a snapshot of one of the figures:

View attachment 174592

https://www.researchgate.net/profil..._expansion/links/543be4550cf24a6ddb97b9e9.pdf

Gene duplication may play a more important role than substitution or indel mutations.

Interesting, lets see what you have here:

Here we provide an overview of the data supporting the view that DUF1220 copy number (dosage) increase is a major contributor to the increase in neuron number, brain size, and cognitive ability that has occurred specifically in the anthropoid sub-order (monkeys, apes, humans) of primates, including the evolutionarily rapid and extreme expansion of the human brain.​

These comparisons are informative, what it underscores is differences:

DUF1220 copy number markedly increasing in monkeys, further in apes, and most extremely in humans where the greatest number of copies (∼272 haploid copies) is found
​

If I have seen one of these comparisons I've seen a dozen, the actual evolution of the divergence is assumed, not demonstrated.

This study surveyed essentially all human genes (e.g., approximately 24,000) and identified 1,004 that showed lineage-specific copy number changes among humans and the 4 great ape species. Of 140 genes identified that showed human lineage-specific (HLS) gain or loss in copy number, the most extreme change was found to be due to sequences encoding DUF1220, a protein domain of unknown function​

A protein domain of unknown function has 1,004 human specific changes and the apes have 4. You want to pass that off as some kind of proof of gene duplication? It's not, these are differences, pure and simple.

Only two bases (out of 118) are changed between chimpanzee and chicken, indicating that the region was present and functional in our ancestor at least 310 million years (Myr) ago. No orthologue of HAR1 was detected in the frog (Xenopus tropicalis), any of the available fish genomes (zebrafish, Takifugu and Tetraodon), or in any invertebrate lineage, indicating that it originated no more than about 400Myr ago (An RNA gene expressed during cortical development evolved rapidly in human)​

More differences, I'll just add DUF1220 if it turns out they actually have anything to do with brain related functions. They have found these protein products included neural genes but there isn't anything substantive demonstrating adaptive mechanism.

a gene that lacks DUF1220 sequences and, when mutated, has been implicated in microcephaly. (Wikipedia)
​

The Wikipedia offers a couple of citations for this:

Bond J, Woods CG (2006). "Cytoskeletal genes regulating brain size". Curr. Opin. Cell Biol. 18 (1): 95–101

Dumas L, Kim YH, Karimpour-Fard A, Cox M, Hopkins J, Pollack JR, Sikela JM (2007) "Gene copy number variation spanning 60 million years of human and primate evolution". Genome Res. 17 (9): 1266–77.
​

Thanks LM, I'll do the background reading and get back to you.

Have a nice day
Mark

​