Vol 45(2011) N 5 p. 704-727;
Repeated DNA Sequences as an Engine of Biological DiversificationEngelhardt Institute of Molecular Biology, Russian Academy of Sciences, Moscow, 119991 Russia
Received - 2010-11-25; Accepted - 2010-12-29
Several aspects of the functional role of nonprotein-coding DNA elements in cell life and taxon evolution are discussed in connection with modern views of three-dimensional regulatory networks as a basis for life support and evolution. A closely related issue is the leading role that duplications or multiplications of any DNA fragments (from single nucleotides to segmental duplications) play in the origination and reshaping of the genome and its interaction with proteins at the chromatin level. Diversities of the genome and chromosome architectonics lead to diversity of morphogenesis by this way. The regulation and plasticity of the genome is determined by the structure, plasticity, and evolution of genomic satellite and dispersed repetitive elements, which, being tightly bound with life phylogeny, result in somatic and inherited changes. Repeated sequences contribute to the epigenetic regulation, which involves repeats themselves, their modifications, or their RNA transcripts. There is growing evidence that a metaphoric description of nonprotein-coding sequences as egoistic, junk, or parasitic is senseless and useless. To the contrary, a hypothesis is formulated that repetitive noncoding DNA could be considered as a main substrate of life, a framework serving as a basis for protein-coding sequences. Molecular evolution of this framework defines the pattern of DNA transcription and, eventually, evolution of structural proteins and morphological differentiation. Genes involved in main energetic, housekeeping, and metabolic processes are thought to form a protective envelope for hereditary material and to provide enzymatic pathways of replication, transcription, and epigenetic regulation.
satellite repeats, dispersed repeats, egoistic and junk DNAs, DNA duplication and multiplication, morphogenesis, biodiversity, molecular evolution