Principle or law of inheritance were enunciated by Mendel. There are four principals or laws of inheritance based on monohybrid and polyhybrid cross.

$(i)$ One gene inheritance

$1.$ Principle of paired factors

$2.$ Law of dominance

$3.$ Principle of law of segregation

$(ii)$ Inheritance of two genes

$1.$ Principles or law of independent assortment