A person can only show a recessive trait if both of their parents carried at least one copy of each of the recessive allele. The parents do not need to show the trait, as one copy is not enough to reveal it, but they must both carry it.
Hope this helped!
Answer:
a mutant dominant allele is expressed in very individual who inherits even one copy points a seriosbdisorder where people can die young and fail to reproduce so basically a dominant allele with die out of population
Think of it this way:
DNA inside cells store all the genetic information on a person's looks, eye colour, hair colour etc. It makes them unique. The analogy of being like books in a library basically suggests that in a library there is so much information and every book is different with different knowledge... That's basically what DNA is; millions of different information things.
