November 6th 2012

Beyond Mendel

I.Incomplete Dominance- when 2 alleles each have an effect when together. 

-There is not a dominant trait/ there is not a recessive trait 
In snap dragons:
P: red x white
F1: all pink flowers
F2: all three colors(red, pink, white)
Phenotypic ratio = 1:2:1

II. Blood typing- Controlled by "2" genes. 

     A. ABO gene: 3 alleles

        1. "A" (I superscript A) = Dominant to O. Co-dominant to B.
        2. "B" (I superscript B) = Dominant to O . Co-dominant to A.
        3. "O"(i) = Recessive

     B. Rh Gene: 2 alleles( for this instance only)

        1. Positive: (+)(R)= Domninant
        2. Negative: (-)(r) = Recessive