Laws of Mendel

Mendel proposed two laws. Those are defined below.

Law of segregation

Hybrids or heterozygotes of F1 generation have two contrasting characters or allelomorphs of dominant and recessive nature. These alleles remain together for long time but do not contaminate or mix with each other and separate or segregate at the time of gametogenesis, so that each gamete receive only one allele of a character either dominant or recessive.

As gametes formed are always pure (carry either dominant or recessive allele not both), this law is also referred principle of segregation or principle of purity of gametes.


Parents Red flower (RR) × White flower (rr)
F1 Pink (Rr)
F2 3Red : 1White

Law of independent assortment

When the parents differ from each other in two or more pairs of contrasting characters or factors then the inheritance of one pair of factor is independent to that of the other pair of factors.


Pea plant, seed characters shape and color considered.

Parents Yellow Round × Green Wrinkled
F1 Yellow Round
F2 9Yellow Round : 3Yellow Wrinkled : 3Green Round : 1Green Wrinkled