Mendelian genetics revolve around the Mendel's laws i.e. law of segregation and law of independent assortment, which Mendel deduced from his observations. To predict the transmission probabilities, the likelihood of a particular allele being inherited from the father is multiplied by the likelihood of a particular allele from the mother. Such outcomes are often summarized in a table called a Punnett square.
Besides the Mendel's dominance and recessiveness rule, dominance is sometimes influenced by techniques for measuring phenotypes. Environmental influences also play a key role in developmental expression. Environmental variables like temperature can affect molecular stability or the rate of a biochemical reaction.