There are four types of linkages present :
1. Complete Linkage - Linkage in which crossing over does not occur is known as complete linkage or absolute linkage.
2. Incomplete Linkage - If some frequency of crossing over also occurs between linked genes, it is known as incomplete linkage.
3. Coupling Linkage - It refers to linkage either between dominant genes or between recessive genes.
4.Repulsion Linkage - It refers to the linkage of some dominant genes with some recessive genes.