Statistical laws of eukaryotic DNA patchiness
Active development of the genetic engineering and expression of foreign genes in various organisms revealed the requirement of the DNA sequences adaptation to the genetic machinery of a host cell including adaptation of both functional elements of the genetic code and its tertiary architecture. The annotated genomes of organisms at different evolutionary levels that are widely used as models were obtained from the Genbank (ftp://ftp.ncbi.nlm.nih.gov/genomes). The probability density functions of the sizes of structural elements of the genetic code were assessed and analyzed. The analysis of the distribution of sequences of coding DNA (genes and exons) and noncoding DNA (intergenic sequences and introns) revealed their universal pattern in genomes of all eukaryotes independently of their evolutionary level, the average number of introns in a gene, their sizes and the total genome size. It allows claiming that mechanisms of genomic reorganizations as a result of insertions, deletions, mutagenesis, duplications and others exhibit universal character. The size of inserted/deleted sites of DNA directly depends on the average size of the respective structural elements of a genetic code (genes, introns, exons) of the organism. Therefore the genetic engineering designs where the DNA donor and recipient are located at different evolutionary levels require the structural elements of foreign DNA being adapted to their average sizes of the host to minimize the negative effects from the reorganization of the genetic machinery of the host.