Genetics
LESSON 2
Non-Mendelian Genetics
Incomplete Dominance
- a third (new) phenotype
appears in the heterozygous
condition as a BLEND of the
dominant and recessive
phenotypes.
Ex - Dominant Red (R) + Recessive White
(r) = Hybrid Pink (Rr)
Codominance
- in the heterozygous condition, both
alleles are expressed equally with
NO blending! Represented by using
two DIFFERENT capital letters.
Example: Dominant Black (B) +
Dominant White (W) = Speckled Black
and White Phenotype (BW)
Rhodedendron
Roan Cattle
Appaloosa horses
Multiple Alleles
- there are more than two alleles for
a gene.
Ex – blood type consists of two dominant
and one recessive allele option. Allele A
and B are dominant over Allele O (i)
