Linkage:
All the genes located on the same chromosome are called linkage genes and the phenomenon as linkage.
Linkage was first demonstrated by Bateson of Punnet in sweet pea (Lathyrus odoratus).
Linkage Group:
Each chromosome showing phenomena of linkage forms one linkage group.
No. of linkage group is equal to the hoploid number of chroms somes in an organisms.
Following are the effect of linkage:
(i) Linked genes fails to separate independently and are therefore always exceptions to the Mendel'* principle of independent assortment.
(ii) Linked genes can be separate and recombine during meiosis
(iii) linked **** in human beings:
Colour blindness and hemophilia (Bleeder' **) are two linked **** in human beings
(iv) Due to the linked gene also observed in the case of Drosophila. T.H. Morgan found that white eye colour is a *** linked character in drosophila.
Importance of linkage:
(i) Linkage studies are good for localising areas of *** risk across the genome
(ii) It is also be used to study multiple genetic Morkers simulatneously.
(iii) Linkage analysis is suitable for single gene defect in the families also called as monogenic disorders.
