Evolution, its not just about genetic mutations any more
Posted: 17 September 2011 02:15 PM   [ Ignore ]
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http://www.sciencedaily.com/releases/2011/09/110916152401.htm

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Posted: 17 September 2011 03:40 PM   [ Ignore ]   [ # 1 ]
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deros - 17 September 2011 02:15 PM

http://www.sciencedaily.com/releases/2011/09/110916152401.htm

Good find…very interesting.

I read once that our DNA contains much unused instructions, i.e. many animals have code for wings, but never use that code to actually make wings.
Humans have a DNA code for growing a tail, but that code is now only used to make a tailbone, not a complete tail.

Perhaps these epigenes are triggers with ability to “test” the environment, after which they send information to the “command codes”, which in turn alter the growth commands, not only what to grow, but also how to grow it. That would mean that evolution is not necessarily a passive (natural) selection of a few “lucky individuals” who manage to survive, but that organisms also have an active triggering mechanism which “experiments” with new approaches for functioning in a particular environment.

I have a feeling that when they really dig into this, they may discover that in a very changeable environment the epigenetics of organisms in that environment play a greater role than in organisms in a very stable (predictable) environment. However it also seems to indicate that there is a real competition for refinement (brighter color, sweeter smell, taller growth) where epigenes actively “try out” different, hopefully more successful, survival techniques rather than depending on pure natural selection.
Thus after many tries, a particularly successful organism may “permanently fix” the command structure in the organism’s DNA. This may account for the much greater activity in the epigenes, than in the DNA coding itself. This would also account for slight differences in flowering plants from a single parent (cloned), which are quite apparent not only to us but also to pollinating insects, which can be very picky in their choice of a symbiotic partnership.

http://www.sciencedaily.com/releases/2007/02/070208230116.htm

[ Edited: 17 September 2011 03:48 PM by Write4U ]
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Posted: 17 September 2011 06:10 PM   [ Ignore ]   [ # 2 ]
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I have no idea what this means in terms of the actual coding in the genome (as if I know anything anyway) but interesting nonetheless. I would only caution that such sentiments as ‘perhaps these epigenes are triggers with the ability to “test” the environment” aren’t the best way to put it, because the phrase implies a kind of design, whereas we know that this is not really how evolution works. Rather, it could be a different level of adaptation (or destruction) by randomization besides the standard gene alteration.

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Posted: 17 September 2011 06:42 PM   [ Ignore ]   [ # 3 ]
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TromboneAndrew - 17 September 2011 06:10 PM

I have no idea what this means in terms of the actual coding in the genome (as if I know anything anyway) but interesting nonetheless. I would only caution that such sentiments as ‘perhaps these epigenes are triggers with the ability to “test” the environment” aren’t the best way to put it, because the phrase implies a kind of design, whereas we know that this is not really how evolution works. Rather, it could be a different level of adaptation (or destruction) by randomization besides the standard gene alteration.

Yes, of course. Testing is the wrong word to use. But you understood my drift. A random trigger would probably a better term. Then this variety is tested against its environment and, if successful, is adapted into the DNA as a permanent evolutionary change. This would certainly account for the incredible variety in a species, even within a single family.

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Posted: 18 September 2011 09:42 PM   [ Ignore ]   [ # 4 ]
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deros - 17 September 2011 02:15 PM

http://www.sciencedaily.com/releases/2011/09/110916152401.htm

{...}
The study, published September 16 in the journal Science, provides the first evidence that an organism’s “epigenetic” code—an extra layer of biochemical instructions in DNA—can evolve more quickly than the genetic code and can strongly influence biological traits.
{...}
“Our study shows that it’s not all in the genes,” said Joseph Ecker, a professor in Salk’s Plant Molecular and Cellular Biology Laboratory, who led the research team. “We found that these plants have an epigenetic code that’s more flexible and influential than we imagined. There is clearly a component of heritability that we don’t fully understand. It’s possible that we humans have a similarly active epigenetic mechanism that controls our biological characteristics and gets passed down to our children.

Pretty fascinating.  It always seemed to me from my simpleton perspective that biological selection alone couldn’t really explain how rapidly entire populations have been know to change, or the speed of species divergence and the rapid radiation of species after extinction events have cleared previously occupied niche’.  Here’s another layer of complexity along with the those jumping genes.  Not that I understand any of it beyond a cartoon level, still it’s one fascinating cartoon.

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Posted: 19 September 2011 10:21 AM   [ Ignore ]   [ # 5 ]
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I always suspected evolution had found a way to “move faster” than we thought it could smile. It is interesting to see that Lamark was actually partially correct, despite being eclipsed by Darwinism (http://en.wikipedia.org/wiki/Lamarckism). Who saw that coming?

Epigenetics is not so new, but this study seems to show that the epigenome can be more influential than previously thought. I first heard about epigenetics after reading about a study of humans that found that living through a famine during preadolescence affected one’s grandchildrens’ risk for cardiovascular disease and diabetes: http://en.wikipedia.org/wiki/Epigenetics#Transgenerational_epigenetic_observations . Really fascinating stuff

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Posted: 19 September 2011 01:26 PM   [ Ignore ]   [ # 6 ]
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domokato - 19 September 2011 10:21 AM

I always suspected evolution had found a way to “move faster” than we thought it could smile. It is interesting to see that Lamark was actually partially correct, despite being eclipsed by Darwinism (http://en.wikipedia.org/wiki/Lamarckism). Who saw that coming?

Epigenetics is not so new, but this study seems to show that the epigenome can be more influential than previously thought. I first heard about epigenetics after reading about a study of humans that found that living through a famine during preadolescence affected one’s grandchildrens’ risk for cardiovascular disease and diabetes: http://en.wikipedia.org/wiki/Epigenetics#Transgenerational_epigenetic_observations . Really fascinating stuff

Even more remarkable, I believe there is reliable data that after a war (killing mostly males), the next generation produces more females. From a survival point, this apparently to make more females available for replenishing the population.
But how do we “genetically know” that more females are required, not males? Is this a function of epigenetics?

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Posted: 19 September 2011 01:52 PM   [ Ignore ]   [ # 7 ]
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Write4U - 19 September 2011 01:26 PM

Even more remarkable, I believe there is reliable data that after a war (killing mostly males), the next generation produces more females.

What data?

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Posted: 19 September 2011 03:03 PM   [ Ignore ]   [ # 8 ]
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Write4U - 19 September 2011 01:26 PM
domokato - 19 September 2011 10:21 AM

I always suspected evolution had found a way to “move faster” than we thought it could smile. It is interesting to see that Lamark was actually partially correct, despite being eclipsed by Darwinism (http://en.wikipedia.org/wiki/Lamarckism). Who saw that coming?

Epigenetics is not so new, but this study seems to show that the epigenome can be more influential than previously thought. I first heard about epigenetics after reading about a study of humans that found that living through a famine during preadolescence affected one’s grandchildrens’ risk for cardiovascular disease and diabetes: http://en.wikipedia.org/wiki/Epigenetics#Transgenerational_epigenetic_observations . Really fascinating stuff

Even more remarkable, I believe there is reliable data that after a war (killing mostly males), the next generation produces more females. From a survival point, this apparently to make more females available for replenishing the population.
But how do we “genetically know” that more females are required, not males? Is this a function of epigenetics?

Going by what you said, it doesn’t sound like it, since epigenetics is about heritable traits. So if the next generation has a higher chance of producing females, that would be epigenetic. This sounds like it’s just an immediate response to the environment, where somehow there’s a higher chance of an X-chromosome-carrying sperm fertilizing an egg (some kind of hormonal change perhaps?). I would be interested in seeing a source too.

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Posted: 19 September 2011 05:26 PM   [ Ignore ]   [ # 9 ]
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domokato - 19 September 2011 03:03 PM
Write4U - 19 September 2011 01:26 PM
domokato - 19 September 2011 10:21 AM

I always suspected evolution had found a way to “move faster” than we thought it could smile. It is interesting to see that Lamark was actually partially correct, despite being eclipsed by Darwinism (http://en.wikipedia.org/wiki/Lamarckism). Who saw that coming?

Epigenetics is not so new, but this study seems to show that the epigenome can be more influential than previously thought. I first heard about epigenetics after reading about a study of humans that found that living through a famine during preadolescence affected one’s grandchildrens’ risk for cardiovascular disease and diabetes: http://en.wikipedia.org/wiki/Epigenetics#Transgenerational_epigenetic_observations . Really fascinating stuff

Even more remarkable, I believe there is reliable data that after a war (killing mostly males), the next generation produces more females. From a survival point, this apparently to make more females available for replenishing the population.
But how do we “genetically know” that more females are required, not males? Is this a function of epigenetics?

Going by what you said, it doesn’t sound like it, since epigenetics is about heritable traits. So if the next generation has a higher chance of producing females, that would be epigenetic. This sounds like it’s just an immediate response to the environment, where somehow there’s a higher chance of an X-chromosome-carrying sperm fertilizing an egg (some kind of hormonal change perhaps?). I would be interested in seeing a source too.

I apologize, the reverse is true. After war it seems there is a mysterious rise in male babies being born.
There are several logical explanations but one fact struck me. It was proposed that males with a high testosterone level tend to produce more male offspring, with several implications as how this may affect the male/female birthrate during and directly after wartime. In addition it seems that male babies show a greater miscarriage rate for the mother, in stressful times.
But underlying all this was the assumption of a selective process as a response to the environmental pressures and societal impact of war and other extended time periods of population extinction. For nature itself such an immediate genetic response (5-20yrs) is rare and evolution is usually counted in hundreds of thousands if not millions of years. Epigenetic?

[ Edited: 19 September 2011 05:39 PM by Write4U ]
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Posted: 19 September 2011 06:05 PM   [ Ignore ]   [ # 10 ]
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From what I read, there doesn’t seem to be a conclusive evidence indicating more males being born during and after war. Also, according to Fisher’s principle, the sex ratio is approximately 1:1 and it’s based on genetics, not epigenetics.

Here is how Bill Hamilton explains it:

1. Suppose male births are less common than female.
2. A newborn male then has better mating prospects than a newborn female, and therefore can expect to have more offspring.
3. Therefore parents genetically disposed to produce males tend to have more than average numbers of grandchildren born to them.
4. Therefore the genes for male-producing tendencies spread, and male births become more common.
5. As the 1:1 sex ratio is approached, the advantage associated with producing males dies away.
6. The same reasoning holds if females are substituted for males through-out. Therefore 1:1 is the equilibrium ratio.

Also, I remember reading somewhere that it has been observed in some birds that the mothers ultimately “decide” on the sex of the baby. The word “decide” may not be used correctly here. What happens is that mothers with a lower status tend to kill their offspring—if it’s a male—before it hatches. The reason for that appears to be that it can be very costly for lower status females to carry for male offspring. How they know the sex of their offspring is a mystery. But it has been proposed that perhaps lower status human female might have a higher number of miscarriages when carrying a male baby for the same reason.

Just a small note here. By “males being costly” I am referring to the evolutionary cost. Basically, a lower status son will have more difficulties procreating when compared with a lower status daughter. Most females are wanted but only the best or average males are.

[ Edited: 19 September 2011 06:21 PM by George ]
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Posted: 19 September 2011 11:10 PM   [ Ignore ]   [ # 11 ]
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George - 19 September 2011 06:05 PM

Just a small note here. By “males being costly” I am referring to the evolutionary cost.

Oh boy, am I tempted to say something here about female costliness but red face perhaps I better not go there   cheese

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Posted: 21 September 2011 04:19 AM   [ Ignore ]   [ # 12 ]
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citizenschallenge.pm - 19 September 2011 11:10 PM
George - 19 September 2011 06:05 PM

Just a small note here. By “males being costly” I am referring to the evolutionary cost.

Oh boy, am I tempted to say something here about female costliness but red face perhaps I better not go there   cheese

A wise decesion.

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