Genomic imprinting is a natural phenomenon resulting in unequal genetic contribution to the developing fetus in a parent-of-origin-specific manner. Normally, an organism would receive one allele per gene from each parent. The expression of some of those inherited alleles is repressed depending on the parent-of-origin. Studies are still being conducted to gain complete understanding of genomic imprinting. Methylation is known to play a role in the process of imprinting. However, the genomic imprints are erased and reset in both germ lines (sperm and oocyte); hence, the process is reversible in early development of the subsequent generation, depending on the sex of the fetus. Importantly, some imprinting errors are known to play a role in human growth abnormalities such as Prader-Willi and Angelman syndromes, Silver-Russell syndrome, and Beckwith-Weidemann syndrome. Genomic imprinting is crucial to proper organismal development, it’s viability, and is significant in mammalian parthenogenesis. …show more content…
describes the role of CTCF, a protein which binds to imprinting control center (ICR) that is responsible for maintaining H19 and Igf2 gene expression. Igf2 gene encodes insulin-like growth factor 2, and is only paternally expressed; whereas, H19 gene encodes growth-suppressing RNA and can only be expressed if inherited maternally. This work supports the kinship theory of genomic imprinting which proposes that parent-specific gene expression evolved at a single locus because it effects individual’s fitness depending on his/her probability of carrying both parental alleles and