Yes, there are mutations. Purple eyes do actually exist! As a rule, though, the traits seen in an individual can be traced back to their ancestors. I say ancestors because there are recessive traits that can spring up later. Other properties can come into play, too. I made a pretty elaborate first of the month comic on inheritance for tomorrow. BRACE YOURSELVES!

Looking at what Gregor Mendel did, it must have been super monotonous. He kept tabs on a lot of properties on a lot of pea plants to formulate his theories. Also, he happened to get super lucky in his pick. For instance, if he had chosen Snap Dragons, he would have had to deal with partial dominance, which is something not present in pea plants.