When decoding the carrot genome, it was found that in a fragment of a DNA molecule the proportion of nucleotides with cytosine is 10%. Using Chargaff’s rule, which describes the quantitative ratios between different types of nitrogenous bases in DNA (G + T = A + C), calculate the amount (in%) in this sample of nucleotides with adenine.
Adenine (A) is complementary to thymine (T), and guanine (G) is complementary to cytosine (C), therefore the number of complementary nucleotides is the same; Chargaff’s rule: (A + T) + (G + C) = 100%
By condition C = 10%
T + A = 100% – (10% + 10%) = 80%
A = T = 80%: 2 = 40%
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