Definition of Genomic Imprinting
Genomic imprinting is such a pattern of inheritance in which a change occurs in a single gene or in a chromosome. This change occurs while the gametes are formed i.e. spermatogenesis (formation of sperms) or oogenesis (formation of ova). It can also be stated as a process in which a gene is expressed according to its nature of being inherited from the father or from the mother.
This type of effects takes place only in sexually reproducing placental animals. Imprinting is one of those patterns of inheritance that do not follow Mendelian laws. Hence, the traits can be passed down from either maternal or parental lines.