(i) Characters are controlled by genes.
(ii) Each gene controls one character.
(iii) There may be two or more forms of the gene.
(iv) One form may be dominant over the other.
(v) Genes are present on chromosomes.
(vi) An individual has two forms of the gene whether similar or dissimilar.
(vii) The two forms separate at the time of gamete formation.
(viii) The two forms are brought together in the zygote.