Investigating the conformity of the second law of Chargaff on variable-length homopolymer fragments in the human genome

Chargaff studies on thefour DNAnucleotides showed that the frequency of A and C is equal to T and G respectively in an organism s genome. This equality in the doublestranded DNA known as Chargaff s first law, which is the result of the formation of The Watson-Creek pairing in the double-helix structure of DNA.The Chargaff s second rule states that the first rule also holds in ssDNA. These tworulescover all the double-stranded genomesexcept organelle genomes1. In this study, we have analyzed the human genome to investigate the evidence of a generalized form of the Chargoff s second rule. Interestingly enough, results reveal that the frequency of the A and C homopolymers is equal to the frequency of T and G homopolymers, respectively.

Keywords:

Chargaff s first law , Chargaff s second law , Homopolymer , Chromosome , Watson-Creek pairing