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# This program will compute the Chargaff ratio for a gene sequence
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# 1. Input
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Gene = raw_input("Enter your gene sequence -> ")
Gene = Gene.upper()
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# 2. Count number of A, T, G, and C
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Number_of_A = Gene.count("A")
Number_of_T = Gene.count("T")
Number_of_C = Gene.count("C")
Number_of_G = Gene.count("G")
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Number_of_A = float(Number_of_A)
Number_of_T = float(Number_of_T)
Number_of_G = float(Number_of_G)
Number_of_C = float(Number_of_C)
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# 3. Compute Chargaff ratio:
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Chargaff = (Number_of_A + Number_of_T) / (Number_of_C+Number_of_G)
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# 4. Print result
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print "\n"
print "The Chargaff ratio for your sequence is : ",Chargaff
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# 5. End
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