Subject: How does mRNA know which trait is dominant or recessive?

In my science class we are studying genetics, and there is one question 
that no one seems to be able to answer.  We know that there are dominant 
and recessive traits, but we don't know how the mRNA decides which one it 
should make.  My teachers came up with two possibilities.  The first one 
is that the DNA decides which trait is going to be made before the RNA 
enters the picture.  The second one is that the RNA makes both dominant 
and recessive traits, and the finished proteins decide which one is going 
to show up in the phenotype.  My class and I would greatly appreciate any 
information you could give us on this subject.  Thank you.
Meghan 
Cermitt13@aol.com

Re: How does mRNA know which trait is dominant or recessive?