Rassidan

Alright so if I am understanding it right for a person to have Amber/Gold eyes you have to have a mutation. What I can't seem to figure out is a mutation of what. Is it more common in certain nationalities? What is this eye color dominant and recessive over, Though I would assume it is recessive over everything. Can it be passed on to children? Everything I have read on this topic has been very basic and I would like to know more of the specifics.