Genes Linked Genes Unlinked Genes When two or more genes are present close to each other on the same chromosome. When genes are present on two non-homologous chromosome During the gamete formation such genes are transmitted together .e. do not assort independently During the gamete formation such genes assort independently
Linkage and linkage group Transmission pattern of linked genes is termed as linkage. All the genes present on the same chromosome forms a single linkage group, .e. during cell division these genes are inherited as one group.
The number of linkage group is equal to the number of chromosomes present in an organism. For e.g.-human females carry 22 pair of autosomes and 2 x-chromosomes hence the linkage group in this case would be 23. Similarly human males carry 22 pair of autosomes and 1 X-chromosome and 1 Y chromosome, hence the linkage group in this case would be 24
Linkage Complete linkage Incomplete linkage When the cross over during the timeWhen after the crossover the of cell division does not affect the linked genes got separated and both parental and recombinant types are formed transmission of linked genes i.e. the linked genes transmit together and there are no recombinants formed
Recombinant Frequency Recombinant frequency is described as the percentage of recombinant offsprings formed after the crossing over occur between the linked genes during the cell division. Number of recombinants Total number of offsprings Recombinant frequency
Linkage mapping It is described as a gene map which determines the relative positions of the genes and distance between them and how often the genes will inherit together. Number of recombinants Total number of offsprings Map distance - 100 Unit of measurement of genetic map is map unit or centimorgan(cM). 1 CM 1% recombination
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