The rules of long DNA-sequences and tetra-groups of oligonucleotides

The article is devoted to hidden symmetries in long sequences of oligonucleotides of single stranded DNA. The notions of tetra-groups of oligonucleotides and also collective frequencies and collective probabilities of members of the tetra-groups are introduced to study hidden tetra-group regularities in mentioned sequences. Each of such tetra-group contains 4 members, each of which combines 4^(n-1) oligonucleotides with the same length n in accordance with their certain attributes. Results of comparison analysis of collective probabilities of separate members of the tetra-groups for a representative set of long nucleotide sequences are shown. These results give evidences in favor of existence of the suppositional tetra-group rules of oligonucleotides in single stranded DNA in addition to the second Chargaff's parity rule.