Human Accelerated Regions (HAR's) are a set of 49 segments of the human
genome that have been shown to be responsible for some of the most important
areas of divergence between humans and chimpanzees. They are known to
be involved in the development of human neuroanatomy, language, and
complex thought. They are also largely responsible for providing us humans with
opposable thumbs and ankle and wrist joints that enabled us to walk upright
and enjoy pornography.
What is most intriguing about these genes is the rate at which they evolved,
taking a mere 6 million years. How did they evolve so quickly and with such
dramatic consequence?
Traditional understanding of Darwinism is that of natural selection. A principle
which, in itself, is undeniable. But is positive selection enough though to drive
evolution to such complexity? (creationists please read on before posting).
Getting back to what we understand natural selection to be then. For most
of us it represents changes in our 3 billion count code that lead to advantages
with respect to our environment which, in turn, lead to the ongoing breeding of those
traits. But at what level does this occur?
SNP's (single nucleotide polymorphism's) in other words, single, mutational
alterations to DNA that become physically evident (phenotypes) are actually<i>not</i>
related to the mechanisms for the rapid evolution of a particular region of the human
genome, in this case, the HAR's or human traits.
DNA is composed of two 'hand-shake' pairs, one called T-A and the other G-C. As mutation
occurs within a genome, one 'hand-shake' may be substituted for another.
However, one hand-shake is like asking a farmer to date his daughter
(G-C) and the other (T-A) is like meeting your favourite boy-band (if you have a
favourite boy-band).
Please excuse the layman's version if you already know this, I don't mean to patronise
anyone (that means talking down to you).
It has been shown that the rate at which soft 'hand-shakes' are transformed into hard
'hand-shakes' is related to the rate at which mutation occurs and hence, evolution occurs.
The evolution is brought about by changing 'junk DNA' into functional DNA.
The disparities in weak-->strong and strong-->weak are called 'bias in divergence sequences'
or BDS (Bad hanD-Shake). The weak-->strong imbalance is called gBGC (G-C based gene conversion).
BDS occurs in both vertebrates and invertabrates, coding and non-coding regions alike but
is biased towards species and sex (favouring mammals and males).
"The presence of BDS in many HARs prompted the suggestion that gBGC, rather than positive selection, may have
generated the acceleration (Galtier and Duret 2007). Thus we
might expect that HARs showing strong evidence of gBGC
would be less likely to have obtained new functions in human. HAR1 and HAR2 (HACNS1), the two fastest evolving
HARs, have strikingly biased substitution patterns. However,
there is strong experimental evidence of function maintenance
in HAR1 (Pollard et al. 2006) and gain in HAR2 (Prabhakar
et al. 2008)—a surprising result if the human-specific changes
in these sequences were created by a purely neutral mutational
process. Therefore, we hypothesize that in some evolutionary
scenarios gBGC substitutions may themselves lead to novel
functions, or may set the stage for later adaptive changes,
perhaps due to compensatory substitutions driven by selection."
http://gbe.oxfordjournals.org/content/early/2011/06/11/gbe.evr051.full.pdf
Ah, so we now have an hypothesis from which to work from.
The hypothesis is that the distribution of base-pairs in a non-functional (junk) region of DNA may in
itself be a force involved in evolution, separate or intrinsic to positive selection.
What other forces than choice could be involved? What indeed are the forces shaping our choices?
I found another article that examines evolution within the context of entropy
"saltations<i>[state changes]</i>, in complexity parlance — appear to be non-linear emergent phenomena, the
result of networked interactions that produce self-organization at ever higher levels. From this perspective,
Darwinian evolution is a mechanism of a higher universal law, perhaps even a variant on the second law of
thermodynamics.
"a mechanism that coordinates the coevolution of species in an ecosystem to effectively capture, process and
dissipate solar energy into the earth’s shadow … an emergent process founded on the same thermodynamic
imperatives that are thought to underlie all self-organization."
Guy Hoelzer - "On the logical relationship between natural selection and self-organization,"
http://www.ncbi.nlm.nih.gov/pubmed/17040375
So how should we really be viewing evolution? It seems positive selection itself seems to imply
some kind of intrinsic understanding of right or wrong. Are we really any differant to creationists for
not questioning this kind of idealism?
Originally posted by Thequ1ckWell, that is a simple question. Science dismisses any sort of "ethereal forces", not because they cannot exist in a fundamental sense, but because we have no mechanism to verify their existence.
The question is this :
Is Darwinian-ism open to the concept of ethereal forces other than
the slog of selection?
Originally posted by sonhouse"The mind is a finer body, and resumes its functions of feeding, digesting, absorbing, excluding, and generating, in a new and ethereal element. Here, in the brain, is all the process of alimentation repeated, in the acquiring, comparing, digesting, and assimilating of experience. Here again is the mystery of generation repeated"
What do you define as 'ethereal force'?
- Ralph Waldo Emerson
I think the real question here is what do you consider to be ethereal forces?
I consider them to be that of entropy and order.
Originally posted by Thequ1ckWhat is 'Darwinism' or 'Darwinian-ism'?
The question is this :
Is Darwinian-ism open to the concept of ethereal forces other than
the slog of selection?
Why invent a concept of 'ethereal forces'?
It seems to me you started with the need for 'ethereal forces' then looked for evidence for it (and have not yet found convincing evidence).
It is more natural in science to assume that no new explanation is needed until an unexplained phenomena is found. Even when the unexplained phenomena is found it is more natural to look for a reasonable explanation rather than to go off on a tangent looking for 'ethereal forces' whatever those may be.
Originally posted by Thequ1ckEntropy is a common concept in physics and information science, there is no need to tie any "ethereal forces" to it.
"The mind is a finer body, and resumes its functions of feeding, digesting, absorbing, excluding, and generating, in a new and ethereal element. Here, in the brain, is all the process of alimentation repeated, in the acquiring, comparing, digesting, and assimilating of experience. Here again is the mystery of generation repeated"
- Ralph Waldo Emerson
I ...[text shortened]... you consider to be ethereal forces?
I consider them to be that of entropy and order.
It's an intriguing concept, though. I took a course in self organization of matter even though it's not really my specific field (which is quantum physics). Perhaps you ought to read up a bit on it, too.
Originally posted by Thequ1ckI was trying to see if you were calling Ethereal forces somehow equating to supernatural forces. I for sure don't.
"The mind is a finer body, and resumes its functions of feeding, digesting, absorbing, excluding, and generating, in a new and ethereal element. Here, in the brain, is all the process of alimentation repeated, in the acquiring, comparing, digesting, and assimilating of experience. Here again is the mystery of generation repeated"
- Ralph Waldo Emerson
I ...[text shortened]... you consider to be ethereal forces?
I consider them to be that of entropy and order.
Entropy and order, those are fully natural effects, not sure how you would be tying them to evolution though.
Entropy is just the loss of available energy or data in a field of similarities. If, say, two liquids are a thousand degrees apart, energy can be extracted from that system but if the are BOTH at a thousand degrees, there is no way you can extract energy from such a system, it is the loss of differences. How do you relate that to evolution?
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Originally posted by sonhouseSince we are in the Science playground, I'll throw in that "ethereal" may relate to "useful fictions." Or maybe not, but here goes anyway.
I was trying to see if you were calling Ethereal forces somehow equating to supernatural forces. I for sure don't.
Entropy and order, those are fully natural effects, not sure how you would be tying them to evolution though.
Entropy is just the loss of available energy or data in a field of similarities. If, say, two liquids are a thousand degrees a ...[text shortened]... energy from such a system, it is the loss of differences. How do you relate that to evolution?
quote:
Is energy real or is it just a useful fiction? Richard Feynman was of the view that
'It [the conservation of energy] is not a description of a mechanism, or anything concrete; it is just a strange fact that we can calculate some number and when we finish watching nature go through her tricks and calculate the number again, it is the same.'
unquote
http://www.furryelephant.com/content/electricity/teaching-learning/language/
For example, "potential energy" makes the conservation of energy law workable. Where does the kinetic energy go? It's "transferred" and "stored" as potential energy, whether due to the change in location of an object in a force field or as matter defined by E=mc^2 or some other way. Curiously, it's just enough to satisfy the law! And if not, then we bring in things like frictional losses, efficiency measures, etc.
Maybe "entropy" plays a similar role.
Originally posted by JS357Science believes that because it has the vocabulary to describe, by doing
Since we are in the Science playground, I'll throw in that "ethereal" may relate to "useful fictions." Or maybe not, but here goes anyway.
quote:
Is energy real or is it just a useful fiction? Richard Feynman was of the view that
'It [the conservation of energy] is not a description of a mechanism, or anything concrete; it is just a strange fact that onal losses, efficiency measures, etc.
Maybe "entropy" plays a similar role.
so it understands. Maybe the dark energy we seek will be found posthumously
in our famed physicists lab-coat pockets.
edit. I'm going to need some more time to digest your post. It' very rich.
Originally posted by KazetNagorraYes, I will. Might take me a couple of days or so.
Entropy is a common concept in physics and information science, there is no need to tie any "ethereal forces" to it.
It's an intriguing concept, though. I took a course in self organization of matter even though it's not really my specific field (which is quantum physics). Perhaps you ought to read up a bit on it, too.
Originally posted by twhiteheadAbsolutely correct as usual Twhitehead. I was watching one of those
What is 'Darwinism' or 'Darwinian-ism'?
Why invent a concept of 'ethereal forces'?
It seems to me you started with the need for 'ethereal forces' then looked for evidence for it (and have not yet found convincing evidence).
It is more natural in science to assume that no new explanation is needed until an unexplained phenomena is found. Even when ...[text shortened]... ather than to go off on a tangent looking for 'ethereal forces' whatever those may be.
'ancient alien' episodes on TV and got interested in the HAR's.