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.
Example
| 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.
Example
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 |