Genomic Imprinting

BACKGROUND Genomic imprinting is the inheritance out of Mendelian borders. Many of inherited diseases and human development violates Mendelian law of inheritance, this way of inheriting is studied by epigenetics. AIM The aim of this review is to analyze current opinions and options regarding to this way of inheriting. RESULTS Epigenetics shows that gene expression undergoes changes more complex than modifications in the DNA sequence; it includes the environmental influence on the gametes before conception. Humans inherit two alleles from mother and father, both are functional for the majority of the genes, but sometimes one is turned off or "stamped" and doesn't show in offspring, that gene is imprinted. Imprinting means that that gene is silenced, and gene from other parent is expressed. The mechanisms for imprinting are still incompletely defined, but they involve epigenetic modifications that are erased and then reset during the creation of eggs and sperm. Genomic imprinting is a process of silencing genes through DNA methylation. The repressed allele is methylated, while the active allele is unmethylated. The most well-known conditions include Prader-Willi syndrome, and Angelman syndrome. Both of these syndromes can be caused by imprinting or other errors involving genes on the long arm of chromosome 15. CONCLUSIONS Genomic imprinting and other epigenetic mechanisms such as environment is shown that plays role in offspring neurodevelopment and autism spectrum disorder.