Genes, phenotypes and populations

[Neo]

I think that Phineas Gage is more illustrative to neurosciences than to Genetics. Genetically, it can be interpreted as the effect of an environmental change (great, dramatic) on a behavioural phenotype influenced by genetics. In simplistic terms, here the expression of some genes in some cells would be changed by the expression of others following an environmental influence.

Not really.

Genetically, on a more deeper level, it can be inferred that one of the functions of the frontal lobe is to rationally govern behavior through higher-order reasoning, abstract conceptualization, and long-term planning, functions which have already been established by the scientific community.

The structure of the brain is determined almost entirely by genetics, mainly I would say because neuroplasticity is not significantly maintained after puberty and it has been shown that it decreases rapidly after six years of age. Even before this time, environmentally-induced change via neuroplasticity has limits, as neuroanatomical structure is essentially genetic in nature.

 

[ryokan]

The structure of the brain is determined almost entirely by genetics, mainly I would say because neuroplasticity is not significantly maintained after puberty and it has been shown that it decreases rapidly after six years of age. Even before this time, environmentally-induced change via neuroplasticity has limits, as neuroanatomical structure is essentially genetic in nature.

I think that it remains yet the old dilemma nature-nurture. The environment plays an essential role in brain development. I don't believe that experimental evidence have discarded an important role to neuroplasticity in adult brains.
Simplifying, the sources of our knowledge on human brain function are the following:
Experimental:
- mainly extrapolated from experiments in other species
- studies in human subjects treated with electricity or chemicals.
Observational:
- Clinical and pathological observations of brain diseases, including mutations and trauma / stroke...)
- Epidemiological studies, as conducted in siblings
- Correlations between behaviour and functional imaging (MRI, TEP..)

So, our knowledge on human brain is, in great measure, indirect and very, very limited.

I think that there is yet need of a lot of new experimental and observational findings to obtain solid conclusions on the role of Genetics in brain structure and function. Furthermore, the importance of this determination could differ among specialized areas/functions.
At other level, as dramatic case of environment on gene expression, I would remember the so called "reaction norms" in Drosophila, where the observed phenotype (number of omatidia) is strongly dependent of both genotype and temperature

 

[BlackVision]

Another strange thing about Black Vision is his name. As if he was, like Korean, and didnt want anyone to know. So he puts Black on his name to suggest that he's black.

This is so ludicrous. "Black Vision" is the name of my band. Is Ozzy Osbourne trying to suggest he's black with his band name "Black Sabbath"?

 

[BlackVision]

Also english not first language, so could be Asian, e.g. korean.

English is my 1st language. I was born was raised in Los Angeles my entire life. Your assumptions and prejudice are quite offending I must say.

 

[marcus]

..."Black Vision" is the name of my band...English is my 1st language. I was born was raised in Los Angeles my entire life...

I retract, with apology, any guesses about you and where you were coming from.

Also, thanks for providing a little bit of background, like the band. Best wishes, whether it is with the music or with the studies at UC.

 

[hitssquad]

Alzheimer's as a disease vs Alzheimer's as a normal feature of aging

Alzheimer is not related to IQ... although obviously IQ don't up with Alzheimer.

• Clinical features at the initial examination of 42 patients with probable Alzheimer's disease were tested for prognostic value at subsequent follow-up of 54 +/- 25 months. These potential prognostic features were of three types: degree of severity features (eg, IQ scores); variable clinical features (eg, extrapyramidal signs); and individual distinguishing features (eg, gender, education, and age).

It is simply a disease

Alzheimer's status as a disease is contradicted by evidence that all humans of all ages exist in some stage of development of Alzheimer's. It has been pointed out by some life extensionists that if it may be true that if we are all gradually developing Alheimer's, we might want to take some preventive actions such as the administratiion of neuroprotective chemicals.

 

[ryokan]

Clinical features at the initial examination of 42 patients with probable Alzheimer's disease were tested for prognostic value

Alzheimer's status as a disease is contradicted by evidence that all humans of all ages exist in some stage of development of Alzheimer's.

This Abstract talks on Alzheimer's disease.

And... What is a disease?
Is prostatic cancer a disease ? All men, if old enough would develop a prostatic cancer.

Overdoing a little, If you understand by disease "some stage of development" of such disease, all we are patients along all our lifetime.

 

[0TheSwerve0]

I've got a quick question about sex chromosomes. What will happen if the one x chromosome is not inactivated in the female? I keep reading about the double doses females will get and that the fetus will be spontaneously aborted if inactivation does not take place. What actually happens when neither is inactivated?