According to principle of independent assortment, the two factors of each trait assort at random and independent of the factors of other traits at the time of meiosis and get randomly as well as independently rearranged in the offspring. Priniciple of independent assortment is applicable to only those factors or genes which are present on different chromosomes. Chromosome have hundreds of genes which show linked inheritance or linkage. Linkage is the phenomenon of certain genes (present on the same chromosome) to remain together and get inherited through generations. The seven characters that Mendel choose were present on 14 chromosomes and so they did not show linkage but if present on 12 chromosomes they would have shown linkage and the principle of independent assortment would not have been discovered.