A naive question on genetics

[Dadface]

The following thought experiment popped into my head when I was driving from the shop;

Consider one set of alleles which is responsible for one of your inherited characteristics.Now suppose that we could swap that set ,without damage or interference,with equivelent sets from one or a multiple number of donors.Are those alleles exactly identical and would there be any change,no matter how slight, to the original characteristic?Expressing this another way, are the genes that you have exclusive to you?
Loads of other related questions spring to mind but I shall leave it here.

 

[Moonbear]

If they are equivalent, then they are the same, by definition. I'm not sure what you're trying to ask.

 

[Dadface]

Thank you Moonbear.What I mean is are they exactly the same in terms of the characteristics that are inherited ?Could there be slight and possibly as yet to be discovered differences?Suppose ,for example,that there were two people who did not have any ancestors in common(going back numerous generations)but who had the same genetic make up.Since these people inherited the majority of their genes from different sources would their inherited characteristics be slightly different or would they be as alike as say identical twins?

 

[Monique]

Genes can have mutations and variations, I think that is obvious. It depends on the function of the gene and the location of the gene swap (the tissue that's affected) what the phenotype will be.

 

[Ygggdrasil]

There are instances in biology where the underlying DNA sequence of a gene is not the sole determinant of how that gene is expressed and how that gene influences the characteristics of the organism. Collectively, these instances fall under the category of epigenetics (see http://en.wikipedia.org/wiki/Epigenetics). Mainly these epigenetic controls consist of regulatory modifications to the genome (e.g. by affecting DNA methylation or packaging). However, in simplified systems (such as bacteria), there is evidence that the randomness (stochasticity) of gene expression and protein-protein interactions can cause phenotypic changes (see Kaern M et al. Nat Rev Genetics 2005, http://dx.doi.org/10.1038/nrg1615 [Broken] and Choi PJ et al. Science 2008, http://dx.doi.org/10.1126/science.1161427).

This area of biology is still fairly new and much remains controversial and poorly understood. However, it is clear that there are many mechanisms by which identical genotypes can lead to non-identical phenotypes.

 

[Dadface]

Wow this is interesting stuff.Thank you everybody.