I am not ignoring the function of genes, or the gene-environment interactions. What I want to know is if behind every "observable characteristic" we can find a protein -or a group of proteins- which is responsible for that trait. The idea comes from a school curriculum, and it is expressed as follows:

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> In this unit the core topic is the central role of proteins as executors of fundamental biological functions and thus as responsible of an organism phenotype...
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Thank you in advance.