To what extent does the environment effect human phenotype?

Question

Having a h**l of a hard time finding the answer in google. I am wondering if the environment plays any significant role in changing human phenotype. For instance, say I were 100% Spanish (like that is possible in today's Europe -- thank you May 9, 1945), and moved to Greece at an early age. What would the phenotypic differences be? Would they be more different if I moved to Africa instead? Antartica? Australia, etc?

Thanks.

Answer 1

The human phenotypes are the result of natural selection in the environments where people exist.  

Let me give you a concrete example.  There is a gene for hemoglobin S, a variant of the normal hemoglobin that carries oxygen in the red blood cells.  The S variant provides protection from malaria if the person has only one copy of the gene.  If the person has two copies, he will have sickle cell disease.

This is a simple mutation which changes only one amino acid in hemoglobin.  The mutation happened twice, once in the Mediterranean Sea area and once in southern Africa.  This is a clear example of the human phenotype responding to environmental pressure.  In this case, the environmental pressure was malaria.

Answer 2

Those charcteristics which the environment affects most easily are polygenic  ones -ie those which are determined by multi genes.Examples are height, weight which can easily be affected by diet especially during years of growth and development.

So your height, weight, stature and may be skin colour, due to differing exposure to sun, may well change.