The Role of Retroelements in the Formation of CNV in the Human Genome in the Development of Diseases

Copy number variations (CNVs) are involved in eukaryotic genomes evolution. CNVs also the causes of multifactorial and monogenic diseases. Retroelements can be causes of CNVs emergence and evolution. Retroelements occupy 42.5% of the human genome and are located mainly in intergenic, intronic and regulatory regions. The mechanisms of CNVs formation are due to non-allelic homologous recombination between retroelements due to their distribution across all chromosomes and the presence of homologous sequences. Role of recombinations between retroelements as causes of neurofibromatosis type 1, Cowden syndrome, Peutz-Jeghers syndrome, Langer-Gideon syndrome, Fanconi anemia, amelogenesis imperfecta, and spastic paraplegia type 4 and other monogenic diseases is described. Mechanisms of CNVs formation using retroelements suggest the role for retroelements as causes of trinucleotide repeat expansion diseases. The influence of LINE1 in Huntington's chorea caused by CAG expansion is described. In fragile X syndrome, CGG expansion occurs in the FMR1 gene, which homologue in Drosophila is involved in retroelements inhibition. In humans, CGG-binding protein influence on Alu and LINE1 described. Role for Alu in GAA expansion identified in Friedreich's ataxia. These relationships suggest the possible retroelements role in triplet code development during the origin of life. At the human population level, the underlying mechanisms of evolution through the influence of retroelements are the cause of numerous diseases. However, in the wild, the same mechanisms serve as substrates for the natural selection of more adaptive traits and eukaryotes evolution.