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Thread: Which traits are purely non-genetic?

  1. #1 Which traits are purely non-genetic? 
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    I'm wondering which traits are not genetic, not in DNA at all, but the only thing I could think of so far is left-handedness or right-handedness. We know this because of identical twins.

    Are there any other traits that are non-existent in DNA?


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    Sort of depends what you mean by "traits"... there's some obvious things like scarring and injury which aren't strictly genetics- though their prevalence in the phenotype could be said to be related to genetic traits. If a tendency to take risks and/or an inability to identify threats have a genetic basis for example. That said, those would probably be the result of a mixture of genetics and cultural inheritance. What I suppose I'm saying is that genetics have an influence far beyond their immediate traits, albeit an influence modulated by environment.


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    I am tempted to think that ALL phenotypes are influenced by genetics, to some extent or other. 8)
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    Quote Originally Posted by tridimity
    I am tempted to think that ALL phenotypes are influenced by genetics, to some extent or other. 8)
    All phenotypes would have to be, by definition. Phenotype is defined as the combination of genetics and environment. But that's not quite the same thing as saying that all traits of that phenotype are influenced by genetics.
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    Quote Originally Posted by TheBiologista
    Sort of depends what you mean by "traits"... there's some obvious things like scarring and injury which aren't strictly genetics- though their prevalence in the phenotype could be said to be related to genetic traits. If a tendency to take risks and/or an inability to identify threats have a genetic basis for example. That said, those would probably be the result of a mixture of genetics and cultural inheritance. What I suppose I'm saying is that genetics have an influence far beyond their immediate traits, albeit an influence modulated by environment.
    So are you basically saying that everything is in our DNA?
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    Quote Originally Posted by VitalOne
    Quote Originally Posted by TheBiologista
    Sort of depends what you mean by "traits"... there's some obvious things like scarring and injury which aren't strictly genetics- though their prevalence in the phenotype could be said to be related to genetic traits. If a tendency to take risks and/or an inability to identify threats have a genetic basis for example. That said, those would probably be the result of a mixture of genetics and cultural inheritance. What I suppose I'm saying is that genetics have an influence far beyond their immediate traits, albeit an influence modulated by environment.
    So are you basically saying that everything is in our DNA?
    No, I'm saying that probably everything about your phenotype is influenced by our DNA, which is not the same thing at all. Take my scarring example- your DNA might, conceivably, influence the frequency and rough distribution of the scars and injuries you pick up during your life, the extend to which they will heal, the extent to which they threaten your life and so forth. That influence will very much be indirect. Your DNA won't control or determine these things, and certainly wont influence these things by itself. Make sense?

    Even with some genetic traits, the control exerted by our genes is more stochastic than deterministic- defining broad parameters to which we adhere during development.
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    Anything you learn is not in your DNA, though your capacity for learning is.
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    You should take a look at Epigenetics. Alternative form of biological data storage.
    http://en.wikipedia.org/wiki/Epigenetics
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    Quote Originally Posted by VitalOne
    Quote Originally Posted by TheBiologista
    Sort of depends what you mean by "traits"... there's some obvious things like scarring and injury which aren't strictly genetics- though their prevalence in the phenotype could be said to be related to genetic traits. If a tendency to take risks and/or an inability to identify threats have a genetic basis for example. That said, those would probably be the result of a mixture of genetics and cultural inheritance. What I suppose I'm saying is that genetics have an influence far beyond their immediate traits, albeit an influence modulated by environment.
    So are you basically saying that everything is in our DNA?
    Did you even read his post? That's nothing like what he said.

    Please define what you mean by "trait" such that a discussion may truly ensue.
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  11. #10 Re: Which traits are purely non-genetic? 
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    Quote Originally Posted by VitalOne
    I'm wondering which traits are not genetic, not in DNA at all, but the only thing I could think of so far is left-handedness or right-handedness. We know this because of identical twins.

    Are there any other traits that are non-existent in DNA?
    Tattoos and piercings immediately come to mind, bound feet and all manners of phenotypes that we impose upon our bodies.
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    Forum Cosmic Wizard SkinWalker's Avatar
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    I'm still not sure what he means by "trait," the term is vague. If he's referring to genetic trait, then obviously there are no traits that aren't genetic.

    Given this obvious argument, I think we can assume his definition of "trait" is more loose. But even if he refers to only those traits that are biological in their manifestation, then the answer is decidedly yes, there exist traits that are not genetic in origin.

    Their origins are cultural.

    An example, in addition to the one's already mentioned, would be artificial cranial modification, where entire cultures of people find a need to shape the cranial vaults of their toddlers such that an aesthetic result is achieved in adulthood, much the same way bonsai trees are cultivated.

    Other traits would be hairstyles, clothing, diet, and dental modifications -each having a biological result in many cases (bald heads tan, some clothing choices also affect melanin).
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  13. #12  
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    I wonder if genes tip the the odds of getting an "innie" or "outie" belly-button?
    A pong by any other name is still a pong. -williampinn
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  14. #13  
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    Quote Originally Posted by SkinWalker
    Quote Originally Posted by VitalOne
    Quote Originally Posted by TheBiologista
    Sort of depends what you mean by "traits"... there's some obvious things like scarring and injury which aren't strictly genetics- though their prevalence in the phenotype could be said to be related to genetic traits. If a tendency to take risks and/or an inability to identify threats have a genetic basis for example. That said, those would probably be the result of a mixture of genetics and cultural inheritance. What I suppose I'm saying is that genetics have an influence far beyond their immediate traits, albeit an influence modulated by environment.
    So are you basically saying that everything is in our DNA?
    Did you even read his post? That's nothing like what he said.

    Please define what you mean by "trait" such that a discussion may truly ensue.

    A trait meaning an inborn attribute, like left-handedness or eye color

    Quote Originally Posted by neird
    You should take a look at Epigenetics. Alternative form of biological data storage.
    http://en.wikipedia.org/wiki/Epigenetics
    Thanks this is very interesting
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    I'd say all 'inborn atributes' are influenced by your DNA. There are some enviromental factors that could cause, in essence, mutations, that wouldn't be inherited. I'm thinking thalidomide and such.

    Also, where are you getting this idea of handedness not being genetically based? It quit obviously is, theres a fair bit of research done into maping the genes that determin it as well. Same for eye colour, how could that possibly not be an inherited trait?
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  16. #15  
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    Conditions around pre and neo natal development draw maternal genetics as environment.
    A pong by any other name is still a pong. -williampinn
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  17. #16  
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    Quote Originally Posted by Pong
    Conditions around pre and neo natal development draw maternal genetics as environment.
    Good point.
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    Epigenetics in the context of an individual’s development, from a zygote to the numerous types of differentiated cells, is a highly complex process. That said, the basis of epigenetics states that the environment—which includes both the internal and external, the macro and the micro—will directly control gene expression through mechanisms other than changes in DNA sequence.

    An example of this is the epigenetic control of cellular differentiation—starting from a zygote cell, cells may differentiate into other cells such as neurons, liver cells, T-cells, muscle cells, etc…all of which possess an identical DNA sequence but will differentiate into cells with a different phenotype and a different function depending on the environment. Expression or inhibition of genes through methylation, demethylation, or other molecular processes will determine whether gene expression takes place.

    Even more interestingly, an epigeneticist will also tell you that gene expression may itself be passed on from one generation to the next, pointing towards transgenerational epigenetic inheritance. Additionally, most forms of cancers, diseases, and developmental abnormalities will have epigenetic origins—dizygotic and monozygotic twin studies clearly demonstrate the profound effect the environment has in influencing human development.

    But coming back to the general question concerned with genetic traits versus epigenetic traits, a clear definition of a epigenetic trait may be helpful, and is characterized as: a stably inherited phenotype resulting from changes in a chromosome without alterations in the DNA sequence. Taking this correct definition of epigenetic traits, I am sure you will find no difficulty in finding some out there.
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