Poorly studied mechanisms of genetic information transmission and hereditary pathology

Nucleotide sequence in nuclear DNA is not the only source of information for phenotype formation. The traits transmitted with mitochondrial DNA along the maternal lineage and epigenetic factors noticeably affect the diversity of organisms. It is known that close relatives may have varying state of energy metabolism in cells of different tissues, up to inherited alterations, such variations resulting largely from the state of inherited mitochondrial DNA. Activity of nuclear genes can vary wit//n broad limits affected by epigenetic mechanisms of regulation, such as X-chromosome inactivation, but also locating satellite DNAs (having different size and copy number) in the nuclear genome regions changing their functions in response to the changes of their structure.