Question

TATA-Pribnow box: Motifs TATAAA or TATAAT of six nucleotides, known as TATA boxes, are an essential part of a promoter site on DNA for transcription to occur. Write a Python program that finds all the TATA boxes in a DNA sequence and reports their types and locations. If there is no such a box, your program should report that as well. Test your program on several DNA sequences with none, and with several TATA boxes of both types. Please use input for DNA sequence and use while and if-else statements.

Answer 1

• Below is the detailed explanation and implementation of the above problem in PYTHON with code and multiple output shown.
• Please read comments for better understanding.
• CODE:

#function which prints occurence of TATA boxes of both types if found as list of indices(starting index) where found
def find(DNA):
#list of TATA boxes
l=['TATAAA', 'TATAAT']
  
#create empty list for both tata boxes to store indices of occurence
ans=[[], []]
#for all kind of TATA boxes
#traverse the DNA sequence
i=0
while i<len(l):
j=0
#traverse the sequence
while j<(len(DNA)-5):
#sequence starting from i of length 6
sub=DNA[j:j+6]
if sub==l[i]:
ans[i].append(j)
j+=1

i+=1
#if not found any
if(len(ans[0])==0 and len(ans[1])==0):
print("No tata boxes found in the DNA sequence!")
#otherwise
else:
k=0
while k<len(l):
if len(ans[k])>0:
print(l[k]+" found at : ",*ans[k])
k+=1
#return
return

#test DNA sequence
DNA=input()
find(DNA)

• INPUT/OUTPUT:

1. TACAAAAG
   No tata boxes found in the DNA sequence!

2. TATAATTATATA
   TATAAT found at :  0

3. TATAAAATATAAAGTATAAT
   TATAAA found at :  0 7
   TATAAT found at :  14

• For better understanding and clarity below are the attached screenshots of the code and input/outputs.

CODE

INPUT/OUTPUT

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