Describe the base pair rule

According to the base pair rule, the purine adenine will always pair with the pyrimidine which is thymine. The purine guanine will always pair with the pyrimidine which is the cytosine. Hence, the concentration of adenine will be equal to the concentration of thymine and the concentration of cytosine will be equal to the concentration of guanine in a given DNA sequence of an individual. This base pair rule is also known as Chargaff's rules of DNA base pairing.