Depending on absence or presence of recombinant phenotype:

a) Complete linkage

• The genes located on the same chromosome do not separate and are inherited together over the generations due to the absence of crossing over.
• Complete linkage allows the combination of parental traits to be inherited as such.
• It is rare but has been reported in male Drosophila and some other heterogametic organisms.

b) Incomplete linkage

• Genes present in the same chromosome have a tendency to separate due to crossing over and hence produce recombinant progeny besides the parental type.
• The number of recombinant individuals is usually less than the number expected in independent assortment

Depending on whether all or some dominant and some recessive genes are linked together:

i) Coupling phase of linkage: Dominant alleles of the linked genes are present in the same chromosome. Eg: Colored full/ color less sunken genes in maize.

ii) Repulsive phase of linkage: Dominant alleles of some genes and recessive alleles of other gene are present in the same chromosome. Eg: Colored shrunken/ color less full genes in maize.