How can an offspring possess a trait that is not seen in the parents?

If the gene was passed down from their grandparents

Hi there!

Sometimes offspring can possess a trait that was recessive in the parents meaning it was not shown in them. It may have been passed down from generations ago and is only surfacing again now.

For example, someones great grandparents may have blue eyes while their grandparents and parents have brown eyes. However, their offspring may also have blue eyes because it was present earlier in the family as a recessive trait.