Linkage is simply the phenomenon by which adjacent genes on the same chromosome stay together and move as a group from generation to generation. It could be said that each block of genes (which basically means a chromosome) constitutes a linkage group. Hence the haploid number of chromosomes would generally be equal to the number of linkage groups in an organism. So we can say that there are 23 linkage groups in man which is equal to the haploid number of chromosomes.