Statistical Analysis Of Base Composition In Human Genome

The first thing to study human genome is to figure out the statistical properties of base composition. In this paper we have studied human genome for the frequencies of occurrence of mononucleotides and oligonucleotides (from dinucleotides to hexnucleotides), and made a research to the form of the performance of the various symmetries in the human genome. Furthermore, then we have compared the statistical features of human genome to an artificial random sequence generated according to Chargaff's second parity rule in mononucleotide level. We found that the human genome would comply with the Chargaff's second parity rule, put another way, it possessed the mirror complementary symmetry. And local deviation has been observed in human chromosomes, and as the length of DNA segment, we observed increases the deviation to Chargaff's second parity rule would decrease to a small extent. Human genome follows Chargaff's second parity rule in large scale, nevertheless, the occurrence of oligonucleotides frequencies in human chromosomes differ with random sequences, and the symmetry inconsistency between them had shown that the obedience to Chargaff's second parity rule for human genome shouldn't be a subsequence of mathematics since the human chromosome sequences are of too long.