Neurons and evolution

[pioneer]

Here is an interesting observation. Our neurons don't replicate beyond a certain point, very early in human life. When we take cellular replication out of the picture, we also take away the primary moving force of evolution, which are genetic changes during cell cycles. The question becomes, why do neurons take this important evolutionary path out of their picture? What is the selective advantage in terms of avoiding this main path of evolution?

[iNow]

Except, your starting premise is mistaken, and consequently so too is pretty much everything which follows.

 

http://en.wikipedia.org/wiki/Neuroplasticity

http://en.wikipedia.org/wiki/Synaptic_plasticity

http://www.nature.com/nrn/journal/v7/n1/execsumm/nrn1809.html

 

 

 

Or here:

 

http://www.sciencedaily.com/releases/2007/10/071015193429.htm

 

"Past theories have suggested that complex brains, like those in monkeys and humans, undergo no changes in brain structure once adulthood is reached," said Gould, a professor of psychology and co-director of the Program in Neuroscience. "These new findings, however, offer further evidence that the primate brain actually shows a remarkable amount of structural reorganization over time. It declines with age, but it does persist at a lower level."

[pioneer]

Good, that saved me time. The cause and effect is based on experience or external potentials inducing neural change. The selective advantage is less impact due the randomness of too much cellular division mutations, allowing more casual control of neural DNA. The DNA becomes much more like a hard drive, with external potentials, writing to the hard drive. The hard drive still has its programs, but these can be advanced via experience and casual control. The program might say hunt X, but through circumstances, the brain rewrites this to say also include Y. This can then be done with education, where adult animals teach the young, what the DNA is not programmed to do, until it does.

[iNow]

DNA doesn't impact which neurons are grown or pruned, only the overall mechanism by which that takes place. Your argument simply doesn't follow. I think it's time for you to stop programming in vBasic.

[CharonY]

Eh, the context is totally wrong. Evolution is about changes in allele frequency. This cannot happen on an individual level (esp. considering that all cells share the same genome).

[Darwinsbulldog]

Eh, the context is totally wrong. Evolution is about changes in allele frequency. This cannot happen on an individual level (esp. considering that all cells share the same genome).

Wrong. Somatic evolution. eg Cancer is a prime example of this.

 

We can work out the probability that an oncogene has been fixed in time (t) with:-

 

P(t) = 1- e ^-Nupt (Nowak, 2006: 220)

 

Where N is the number of cells in a compartment, u is mutation rate per gene per cell, p is the Moran process [1-1/r /1-1/r ^N], t=time

 

Although all cells share the same genome, cells are compartmentalised and specialised, and face different environmental challenges, and have different genes expressed.

 

REF:-

Nowak, M. A. (2006). EVOLUTIONARY DYNAMICS: Exploring The equations of Life. London, Harvard University Press.

[CharonY]

Well, somatic evolution is more of ecological interest seeing the body as a population of cells. However they are really only applicable in terms of tumorigenesis and immune development. This is a very specialized application of evolutionary theories and is not clearly in line what is stated in the OP.

[emrekanca]

My way of thinking evolution is it only occures when gens has changed which is contained by sperm and egg that are going to creat zygote and going to be chosen by nature. Of course thats for the creatures whose reproducting is by sex.Rest of the cells situation is only important for creatures life.