Dihybrid inheritance= show the inheritance of two differentcharacteristics cause by two genes which may be located on different pairs of homologouschromosomes.
Each gene can have two or more alleles.
Expected phenotypical ratio= 9:3:3:1
Ratio may differ because
The fertilisation of gametes is a random process so in a small sample a few chance events can lead to a different ratio.
Genes being studied are both on the same chromosome. They are linked so no crossing over occurs so characteristics will be inherited together.
