PinkMonkey Online Study Guide-Biology
7.6 Law of Segregation
Mendel performed monohybrid crosses separately for each of the seven pairs of contrasting characters. In each such cross, he got similar results as described for the Tall x Dwarf cross. On the basis of the results obtained for the monohybrid crosses, Mendel formulated the law of segregation, also called Mendelís second law of heredity.
The law states that when a pair of alleles is brought
together in hybrid union, the members of the allelic pair remain
together without mixing, diluting or altering each other and separate
or segregate from each other when the hybrid forms gametes.
Thus, according to this law, when the hybrid tall (Tt) in the above experiment forms gametes, the factors T and t shall separate (segregate) and enter different gametes. As a result, the hybrid shall form two types of gametes; those with (T) factor and an equal number with (t) factor. Since each gamete will be pure for tallness or for dwarfness, the law is also known as the law of the purity of gametes.