Definition : Alleles coming from the same parent tend to enter the same gamete and are together in most cases. This phenomenon called coupling similarly, genes coming from different parent tend to enter different gametes and to be inherited separately – independently in most cases. This phenomenon is called Repulsion.
Introduction :
When two alleles P and L , both dominant p and l both execessive came from same parent
( PP LL X pp ll ) tend to enter same gamete. This phenomenon called coupling
Consider
But, in this case, when two alleles, P and L (both dominant forms) coming from different parents, they tend to enter different gamete and remain apart.
This phenomenon called Repulsion.
Subtitle -1 :
No satisfactory explanation of coupling and repulsion was given until morgan (1910) found a similar situation in Drosophila and saw that coupling and repulsion are, two aspects of the single phenomenon called Linkage.
- He supposed that this tendency of linked genes to remain in their original combination was due to their residence on the same chromosome.
- He also suggested that degree/strength of linkage depends on the distance between linked genes in the chromosome. This soon developed into theory of Linkage arrangement of genes and has led to construction of Genetic Map/Linkage Maps of