Proposal: Human Brain Evolution

[Loudmouth]

First I've heard of it, you've been arguing that divergence between chimps and humans is proof. That is begging the question of proof on your hands and knees. Mutations in brai related gene produce disease death and disorders.

Then how do you explain the fact that these genes differ in sequence and yet they don't cause disease?

Because the differences were by design, they are different because they have been since the original creation.

If a designer can change those genes without causing disease, then why can't mutations produce the exact same difference and not cause disease?

 

[lesliedellow]

I am not well versed in molecular biology,

That's alright. He isn't either. A bit like Michael and astrophysics.

 

[FrumiousBandersnatch]

This is what has happened, you did a quick Google search and found nothing but disease and disorder resulting from mutations in brain related genes. Now you have nothing but that circular question that demands a negative because all the positive proof indicates disease death and disorder. Welcome to the inevitable downward spiril.

It's worth remembering that we know of more deleterious mutations in brain-related genes because they've caused those diseases and disorders - we were looking for them. Neutral or beneficial mutations very rarely leave obvious evidence that way.

 

[FrumiousBandersnatch]

JFYI I recently came across a nice example of a beneficial mutation in a brain-related gene - one that confers immunity from Kuru.

"This is a striking example of Darwinian evolution in humans, the epidemic of prion disease selecting a single genetic change that provided complete protection against an invariably fatal dementia," Dr. John Collinge, the senior author of the study and a professor of neurodegenerative disease at University College London, said in a statement."​

 

[mark kennedy]

JFYI I recently came across a nice example of a beneficial mutation in a brain-related gene - one that confers immunity from Kuru.

"This is a striking example of Darwinian evolution in humans, the epidemic of prion disease selecting a single genetic change that provided complete protection against an invariably fatal dementia," Dr. John Collinge, the senior author of the study and a professor of neurodegenerative disease at University College London, said in a statement."​

I don't know if your following this thread but this is what I got from the article at the heart of the discussion:

Over many years, the MRC Prion Unit at the UCL Institute of Neurology has studied a prion disease called kuru which at one time was widespread in a remote area of the Papua New Guinea highlands. Kuru is caused by the same strains of prions that cause CJD and was spread in a community – the Fore – who used to consume their dead as a mark of respect at mortuary feasts. This led to a major epidemic of this prion disease which, at its height in the late 1950’s, caused the death of up to 2% of the population each year.
​

It doesn't take a degree to to realize the a neurogenerative disease is deleterious. The fact that maybe in extreme circumstances there are rare beneficial effects does not constitute a molecular mechanism for the adaptive evolution of a brain related gene.

Have a nice day,
Mark

 

[mark kennedy]

It's worth remembering that we know of more deleterious mutations in brain-related genes because they've caused those diseases and disorders - we were looking for them. Neutral or beneficial mutations very rarely leave obvious evidence that way.

I have two words for you, variant alleles, how many of them do you think brain related genes actually have?

 

[FrumiousBandersnatch]

...It doesn't take a degree to to realize the a neurogenerative disease is deleterious. The fact that maybe in extreme circumstances there are rare beneficial effects does not constitute a molecular mechanism for the adaptive evolution of a brain related gene.

I don't know how you managed to misread the part of my post you quoted, but it is about a mutation that confers immunity from Kuru. As far as I know, there are no beneficial effects from Kuru, rare or otherwise.

 

[FrumiousBandersnatch]

I have two words for you, variant alleles, how many of them do you think brain related genes actually have?

Alleles are variant genes. I have no idea how many alleles brain-related genes have, but it's a lot - and even alleles of seemingly unrelated genes (e.g. the fat mass and obesity-associated [FTO] gene) can have effects on the brain. Nevertheless, despite all these alleles, brain function in the population generally continues to be good enough to promote survival, which suggests most such mutations are not significantly detrimental.

Why do you ask?

 

[loveofourlord]

I do this from time to time and evolutionists run for the trees but here goes. I am proposing a debate with an evolutionist who wants to defend the concept that the evolution of the human brain from that of apes has a molecular basis. Willing to discuss the specifics and the parameters of course, hoping for an honest open discussion.

Grace and peace,
Mark

easy, we know the breaking of one gene played a key part by allowing the jaw strength muscle to decrease allowing for brain to grow bigger.

 

[mark kennedy]

easy, we know the breaking of one gene played a key part by allowing the jaw strength muscle to decrease allowing for brain to grow bigger.

And they know that from gene comparisons and little else. Sure it's easy, just call divergence a mutation like indel or single base substitution and PRESTO!, there's your explanation. Except it begs the question of evidence as to the cause.

 

[mark kennedy]

Alleles are variant genes. I have no idea how many alleles brain-related genes have, but it's a lot - and even alleles of seemingly unrelated genes (e.g. the fat mass and obesity-associated [FTO] gene) can have effects on the brain. Nevertheless, despite all these alleles, brain function in the population generally continues to be good enough to promote survival, which suggests most such mutations are not significantly detrimental.

Why do you ask?

Brain related genes do have variant alleles, invariable they are deleterious.

A commonly carried C677T polymorphism in a folate-related gene, MTHFR, is associated with higher plasma homocysteine, a well-known mediator of neuronal damage and brain atrophy. (Neuroimage Clin. 2012)

Some Research has linked the low-expressing alleles of the 5-HTTLRR to increased risk for being high on anxiety-related personality personality traists such as neuroticism (Handbook of Developmental Psychopathology
edited by Michael Lewis, Karen D. Rudolph)
​

This is one of the most consistent and easily defending points I've discovered over the years and counter arguments appear to be non-existent.

 

[loveofourlord]

And they know that from gene comparisons and little else. Sure it's easy, just call divergence a mutation like indel or single base substitution and PRESTO!, there's your explanation. Except it begs the question of evidence as to the cause.

no they know that because we carry the same gene that causes the jaw strength in great apes, but also would prevent us from speaking and have smaller brains, explain why we would have a broken gene that would cause us to lose most of what makes us humans if we didn't evolve from a species that used to have that activated?

 

[mark kennedy]

no they know that because we carry the same gene that causes the jaw strength in great apes, but also would prevent us from speaking and have smaller brains, explain why we would have a broken gene that would cause us to lose most of what makes us humans if we didn't evolve from a species that used to have that activated?

The MYH16 protein doesn't represent a molecular mechanism, it represents a difference in Ape and Human DNA. What might have happened remains idle speculation, it's just one of many differences that are attributed to changes that must of happened with no explanation how.

 

[FrumiousBandersnatch]

Brain related genes do have variant alleles, invariable they are deleterious.

Invariably? Would you consider immunity from prion diseases, such as Kuru and Creutzfeldt–Jakob disease, deleterious?

​

Once could consider the genetic changes involved in human brain evolution to be the largest set of beneficial examples, but there are others - for example, a mutation that reduces the amount of sleep needed.

This is one of the most consistent and easily defending points I've discovered over the years and counter arguments appear to be non-existent.

Lol.

 

[loveofourlord]

The MYH16 protein doesn't represent a molecular mechanism, it represents a difference in Ape and Human DNA. What might have happened remains idle speculation, it's just one of many differences that are attributed to changes that must of happened with no explanation how.

the mechanism is mutations wich we know occur, a mutation that broke the gene would allow for the brain to grow bigger, and for speach to be more possible, the breaking of the gene is part of the mechenism for how a brain got bigger, not the whole story but it's a good start. This is elementary school biology here.

 

[mark kennedy]

Invariably? Would you consider immunity from prion diseases, such as Kuru and Creutzfeldt–Jakob disease, deleterious?

Well there's definitely protein evolution going on here and it's the result of a single base substitution. While it offers complete resistance to mad cow disease I don't think we are looking at brain evolution.

​

Once could consider the genetic changes involved in human brain evolution to be the largest set of beneficial examples, but there are others - for example, a mutation that reduces the amount of sleep needed.

A comparative genetics study and some vague gene study related to sleep. The first one led me a merry chase and nothing tangible, the benefit was clear but the gene being involved in neuro-development or regulation wasn't all that relevant. Nice try though, imagine what you could come up with if you ever took this seriously.

 

[mark kennedy]

the mechanism is mutations wich we know occur, a mutation that broke the gene would allow for the brain to grow bigger,

No it wouldn't, it would most likely kill the first fetus effected by it.

and for speach to be more possible, the breaking of the gene is part of the mechenism for how a brain got bigger, not the whole story but it's a good start. This is elementary school biology here.

Except it would never get started, brain related genes are called highly conserved for a reason, selective coefficients, functional constraints, synergistic epistasis. Mutations in brain related genes invariably cause disease, disorder and death. Your assuming the mutation breaking the gene is going to do so without derailing the function and I'm telling you it doesn't happen in brain related genes. This isn't elementary school genetics, this is cutting edge stuff researchers have been searching out for decades and still have no explanation for the three fold expansion of the human brain from that of apes.

Begging the question of proof isn't an argument, it's an argument that never happened.

 

[loveofourlord]

No it wouldn't, it would most likely kill the first fetus effected by it.



Except it would never get started, brain related genes are called highly conserved for a reason, selective coefficients, functional constraints, synergistic epistasis. Mutations in brain related genes invariably cause disease, disorder and death. Your assuming the mutation breaking the gene is going to do so without derailing the function and I'm telling you it doesn't happen in brain related genes. This isn't elementary school genetics, this is cutting edge stuff researchers have been searching out for decades and still have no explanation for the three fold expansion of the human brain from that of apes.

Begging the question of proof isn't an argument, it's an argument that never happened.

Not all mutations are bad even in the brain, of course with something that importannt it be highly conserved, since most bad mutations would die before birth, but any neutral mutations or beneficial are more likly to stick, and evolution doesn't require even more then 99.999% chance of it being beneficial as that helps.

 

[FrumiousBandersnatch]

...While it offers complete resistance to mad cow disease I don't think we are looking at brain evolution.

It's a genetic change spreading through that population, which makes it part of the process of evolution; and if it becomes fixed, their brains will have evolved, by definition. It seems unlikely that it will become fixed though, as the practice of brain eating has all but died out, which means the selection pressure is easing.

Nevertheless, if it were true that mutations in brain-related genes were invariably deleterious, you would not expect to see multiple mutations in brain-related genes across generations without apparent detriment, and you'd expect to see all such genes highly conserved across populations. But this isn't the case. Critical areas are highly conserved, but the rest have considerable variation.

imagine what you could come up with if you ever took this seriously.

Indeed.