python2.7 实现 DNA反向互补

想通过python2.7 写一段程序，实现 DNA反向互补，如下列字符串：由文本文档1.txt输入（由文档输入是关键）

ccccgtatcgccaagggcaaggtcatcatcggcaacggcggtgcagagttcggcgcccgtggctttgtgacggcgtatgacgctgaaacgggcaagatggactggcgcttcttcaccgttccgaaccctgacaacaagccggacggcgcagcgtctgacgacgtgctgatgtccaaggcttatccgacatggggcaagggcggcgcatggaagcagcagggcggtggcggaaccgtctgggattcgctgatctatgaccccgtaacggatcttgtttaccttggcgtcggcaacggctcaccctggaactacaagttccgctcggaaggaaaa

ntComplement = {'A':'T', 'C':'G', 'T':'A', 'G':'C'}

返现互补后的结果输出到文档 1rv.txt

 def DNA_complement(sequence):
    sequence = sequence.upper()
    sequence = sequence.replace('A', 't')
    sequence = sequence.replace('T', 'a')
    sequence = sequence.replace('C', 'g')
    sequence = sequence.replace('G', 'c')
    return sequence.upper()

def DNA_reverse(sequence):
    sequence = sequence.upper()
    return sequence[::-1]

使用：
file_name = '1.txt'
data = []
for line in open(file_name):
    line = line.split()
    data.append(DNA_reverse(DNA_complement(line)))

正告楼下抄袭本人回答的无耻之徒，本人坚持投诉到底，直到封号为止！

 import sys
def DNA_complement(sequence):
    sequence = sequence.upper()
    sequence = sequence.replace('A', 'T')
    sequence = sequence.replace('T', 'A')
    sequence = sequence.replace('C', 'G')
    sequence = sequence.replace('G', 'C')
    return sequence.upper()

def DNA_reverse(sequence):
    sequence = sequence.upper()
    return sequence[::-1]

file_name = '1.txt'
f = open(file_name)
f1 = open(r"1rv.txt", "a+")
line = f.readline()
s = ""
while line:
    s = s + (DNA_reverse(DNA_complement(line)))
    line = f.readline()
f1.write(s)
f.close()
f1.close()

1.txt
ccccgtatcgccaagggcaaggtcatcatcggcaacggcggtgcagagttcggcgcccgtggctttgtgacggcgtatgacgctgaaacgggcaagatggactggcgcttcttcaccgttccgaaccctgacaacaagccggacggcgcagcgtctgacgacgtgctgatgtccaaggcttatccgacatggggcaagggcggcgcatggaagcagcagggcggtggcggaaccgtctgggattcgctgatctatgaccccgtaacggatcttgtttaccttggcgtcggcaacggctcaccctggaactacaagttccgctcggaaggaaaa
1rv.txt
AAAACCAACCCACCCCAACAACAACAACCACCCACACCCCAACCCCACCCCAACCAAAACAACAACCCAAACCCCCACAAACAACACCCAAACCCACACCCAACCCCCACCCCCCACCACCAACCAACCCCCCCCCAACCCCCAACACCCAAAACCCAACCACAACACCACCACCACACACCCACCCCCCACCCCCAACAACACACCCAACCCAACCCACAACAACCCCCACACCAACAACCCCCAAACACCCACAAACCCCCACACAAACCCACCCCCCCCCAACACACCACCCCCCAACCCCAACAACACCAACCCCAACCCCAAACCCCC

您好，结尾处 aaggaaaa 反向互补后应该变成结果序列的开头部分，因该是 ttttcctt ，不是AAAACCAA，好像 a 都没有反补，是吗，
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