Differential expression of same gene depending on parent of origin is referred to as –
The phenomenon referred to as genomic imprinting leads to preferential expression of an allele depending on the parental origin.
Genomic imprinting
Human inherits two copies of each gene, i.e. two alleles, from homologous maternal and paternal chromosomes.
There is no functional difference between the genes derives from mother or the father.
But, with respect to some genes, there are functional differences between the paternal gene and maternal gene.
These differences result from an epigenetic process, called genomic imprinting.
In most cases, genomic imprinting selectively inactivates either the maternal or paternal allele.
Maternal genomic imprinting :
Selective inactivation of maternal allele.
Example is Angelman syndrome.
Paternal genomic imprinting :
Selective inactivation of paternal allele.
Example is Prader – Willi syndrome.
Genomic imprinting
Mosaicism
Anticipation
Nonpenetrance