Genetic imprinting more commonly known as genomic imprinting is a normal form of gene regulations that causes obe of the two set of paternal chromosomes to be expressed. We inherit two copies of genes
one from mother and the other from father. Amidest this, both copies of each genes are active or turned on, but in some cases however only one of the two copies is active. Some genes are normally active only
if they are inherited from mother while the others are active only they are inherited from father is their activation depends on their parental source of origin and depends upon sex parents.
The genes undergoing genomic imprinting are generally methylated this methylation of genes act as a stamp. The molecules identify which copy of a gene is inherited from the mother and which one from
father. This addition and removal of methyl groups can be used to control the activity of genes.
A very small percent of human gene undergoes genomic imprinting but the cause is still not known, Also the imprinted genes seen to cluster in the same region of chromosomes.
Eg - Praden Willi syndrome and Angelman syndrome are two distinct disease caused by a deletion in the same part of chromosome 15 when this deletion occurs on the chromosome 15 that come from the father, the child will have Prader Willi syndrome. However when the deletion occurs on the chromosome 15 that
came from the mother, the child will develop Angelman Syndrome. This occurs because gene located in this region undergo genomic imprinting.
It is not sequence based mechanism of inheritance but rather a inherited chemical change to a DNA sequence, is referred to as imprinting. The reason for which this imprinting is important is because of the
chemical modifications, which is passed on from the mother or father to offspring changes the function of the gene or gene product , whether it's expression or actually the function of the gene product itself.