One of creators of quantum mechanics P. Jordan in his work on quantum biology claimed that life's missing laws were the rules of chance and probability of the quantum world. The article presents author’s results of studying probabilities of nucleotides on so-called epi-chains of long DNA sequences of various eukaryotic and prokaryotic genomes. DNA epi-chains are algorithmically constructed subsequencies of DNA nucleotide sequences. According to the algorithm of construction of any epi-chain of the order n, the epi-chain is such nucleotide subsequence, in which the numerations of adjacent nucleotides differ by n (n = 2, 3, 4,…). Correspondingly each epi-chain of order n contains n times less nucleotides than the original DNA sequence. The presented results unexpectedly show that nucleotide probabilities on such DNA epi-chains of different orders are practically identical to nucleotide probabilities in the original long DNA sequence. These data allow considering DNA as a regular rich set of epi-chains, which can play a certain role in genetic and epigenetic phenomena as the author belives. Appropriate rules of nucleotide probabilities on epi-chains of long DNA sequences are formulated for further their tests on a wider set of biological genomes. These phenomenological data and their possible biological meaning are discussed.