Python文字列索引付け/印刷エラー

Question

dna読み込みスクリプトが正しく機能するようにしようとしましたが、現在は部分的にしか動作しません。これは、 'A'、 'T'、 'C​​'、または 'G'文字列を取り、部分文字列が 'ATG'で始まり、 'TAA'、 'TGA'、 'TAG' 。 printAllGenes（）は、見つかったそれぞれの行のdnaストランド（特定された部分文字列）を新しい行に出力し、見つからなくなるまで入力文字列を続けます。 findAllGenes（）はfindStopCodon（）のelse節のエラーのために実行を完了できないようです。

gene_sequence = 'AACCCTAACCCTAACCCTAACCCTAACCCTAACCCTAACCCTAACCCTAACCCTAACCCTAACCCTAACCCTAACCCTAACCCTAACCCTAACCCTAACCCTAACCCTAACCCTAACCCTAACCCTAACCCTAACCCTAACCCTAACCCTAACCCTAACCCTAACCCTAACCCTAACCCTAACCCTAACCCTAACCCTAACCCTAACCCTAACCCTAACCCTAACCCTAACCCTAACCCTAACCCTAACCCTAACCCTAACCCTAACCCTAACCCTAACCCTAACCCTAACCCTAACCCTAACCCTAACCCTAACCCTAACCCTAACCCTAACCCTAACCCTAACCCTAACCCTTAACCCTAACCCTAACCCTAACCCTAACCCTAACCCTAACCCTAACCCTAACCCTCACCCTTCTAACTGGACTCTGACCCTGATTGTTGAGGGCTGCAAAGAGGAAGAATTTTATTTACCGTCGCTGTGGCCCCGAGTTGTCCCAAAGCGAGGTAATGCCCGCAAGGTCTGTGCTGATCAGGACGCAGCTCTGCCTTCGGGGTGCCCCTGGACTGCCCGCCCGCCCGGGTCTGTGCTGAGGAGAACGCTGCTCCGCCTCCGCGGTACTCCGGACATATGTGCAGAGAAGAACGCAGCTGCGCCCTCGCCATGCTCTGCGAGTCTCTGCTGATGAGAACACAGCTTCACTTTCGCAAAGGCGCAGCGCCGGCGCAGGCGCGGAGGGGCGCGCAGCGCCGGCGCAGGCGCGGAGGGGCGCGCCCGAACCCGAACCCTAATGCCGTCATAAGAGCCCTAGGGAGACCTTAGGGAACAAGCATTAAACTGACACTCGATTCTGTAGCCGGCTCTGCCAAGAGACATGGCGTTGCGGTGATATGAGGGCAGGGGTCATGGAAGAAAGCCTTCTGGTTTTAGACCCACAGGAAGATCTGTGACGCGCTCTTGGGTAGAGCACACGTTGCTGGGCGTGCGCTTGAAAAGAGCCTAAGAAGAGGGGGCGTCTGGAAGGAACCGCAACGCCAAGGGAGGGTGTCCAGCCTTCCCGCTTCAACACCTGGACACATTCTGGAAAGTTTCCTAAGAAAGCCAGAAAAATAATTTAAAAAAAAATCCAGAGGCCAGACGGGCTAATGGGGCTTTACTGCGACTATCTGGCTTAATCCTCCAAACAACCTTGCCATACCAGCCCATCAGTCCTCTGAGACAGGTGAAGAACCTGAGGTCGCAGGAGGACACCCAGAAGGTCCAGAGAGAGCCTCCTAGGCCCCCCACCTCCCCCCGTGGCAGCTCCAACCCCAGCTTTTTCACTAGTAAGGCAGTCGGGCCCCTGGGCCACGCCCACTCCCCCAAGCGGGGAAGGAGCTTCGCGCTGCCGCTTGGCTGGGGACTGGGCACCGCCCTCCCGCGGCTCCTGAGCCGGCTGCCACCAGGGGGCGCGCCAGCGGTGTCCGGGAGCCTAGCGGCGCGTGTGCAGCGGCCAGTGCACCTGCTCTGGCCCTCGCCGCGGTCTCTGCCAGGACCCCGACGCCCAGCCTGACCCTGCCATTCAGCGGGGCTGCGGCTCCACGGCCTGCGACAGCAGCCCCACCTGGCATTCAGCGCGCTCCCGGGGGCAGAGGTCGCGGTGTCCTCACGCTGTGGTGCCGGCCTACAACCCCCACGCCGGGCTCGGGCCCGGCGGAGGAGGGCGATGCTCCCCGGGTAGGACAAACCGGTCACCTGGGCTGCGACGGCGGCTTAGGGGCAGAAGCGGCGGTCCAGGGCCGCCTGGCGCAGCAGCCTGTCCCAGCCGCGGTCCCTGCAGTCCCTCCCTGGCGGCTGCGCAGCCGTCCCACGACAGGGGCCATAAACTCTCCAGAGCGGAAAGCCGCACCCTGGTGGCCCGGCCCCGCGCCCAGACCTGGCGGCCGCTGGCACCTGACCCGCTGCATGGGTCTCCAGGGAGCTCGCTGCCCACCCGGCGCTGCAGGCTCGGCTCCCTCGTACACTCTCTGGTAGGTGCTAGGGACGACCCTATGGGCCAGCTTGCCATGCCCAGTCCCCAGGCCGCACCCACCCTGGCTCCCTGGGCTAGGGGACTGGCTCCTCCTGTGAGTCGTGGGTCTGGGAGGCAGGGGCGTTAGGGGAGAGTGAGGGACCGAGGGCAGCCCCTGCTGTGTGCACAGCGAGGTCGTGCACAGGCGTCTGTTGCAGAGCGTGCAGCTTCAGATGAGACTGGATTGCAGGTGGAGATGACTGTGGGTGCGCACACCTGGAGGTGAAGGGGAGGCAGCCTGTCTACCTGACCCATGAAATACAGGAGACTGTACCCCAGAAGCAGCGGGTTCACTGCTCCATTGATTAAGCAAGTCTGGGACACACATGTAGCTAAGCTGTGAGTTCTGTACCAGCGATCCCAACACCCACGCCCTCAGAAAGACACTGGTGTGGGGCCTGGGTGCTTGTCAGGCCTGAAAGTGGAGAGCACGGGCCAGAGACACTGAGTAGGGGGAACCCACCCTAGGGCTCTGAGGGACGACGATGTGGGGAGCTGGTGACAGAGCCTGAGCTGGCCCAATGTTGCACGGTGGGGACAGATTCGAGGTACAGTGGGGACTGGTGACCTCAGTTCCCAGTGTCCCAGCCTGGCCTCCCAGTCCACCCAGCAATTAGTGGGTGCTGCCCTGCAAAGACTCTGGGGGTGCCTCAGCCCTCCTCATCACACGTGACTGGTGACTTCTGTGTCCACCCGCACAATAAGAGGGATCTTCTCTCACTTTCAGGCAAGCCCAAGAAAGTCAGGGGCCTATGTGAGCCAAAGAGGAGAGAAGGTGATGCCTCAGCCCAGTGTTTCTGCCCCACCTCGCTTGTGGCCTTCGGAACTTGATTTGCACCGCAGGAAAATGGGCAATGAAAACCCCTCCCTAACTGGCTTCTCAGTCCACTCTGACCAGCCCACTGCACAGCGCCCACCCTGCAGCTCCAGGTACAGAGGCTGGGATGGCTCTGGGCTGACCTAAGGGCCTTCTGATGGCTCCAACCCTCGGGATGCCTCATGCTCACCCTTTGGCACCCACCTGACAGCTCAGCATCTCTGCTCTCTGCCATCCTCAATGCCTGCTCTAGACAAGCCCAAGTCCCCCAGGAGTGGCAGAGGGAACTGAGCCGAAAACTAAGTCTCGGCTCACTGAACCCCAAGTGGGCTGTCCAGCCTCGCCCTTCAGTTCACAACCCCAGGCAGGTTCCCTCCAGGGATGTGATCCCAGGGGCCACAGCAGCACATTCTGGCCTAACCTATCCACTATTTAAACAGTTACTGAAAAGGCCAGGATGGCCGTGGGCCCTGACATTAATCCCCTTTCTCTGTGAGGGGGCTGGGTTGGGTTTGCCATCCTGATGTCTTTGTGGAAAGAGCTGGCAGGTGAAGCAAGTCTCAGGGGCCAGCCATGGGACAAGGAACCTAGGACTGGCCTCTGCTGGAACCCTCTGAGGCCCCTGCGGACAGGAGGATCCAATGGAGGTCTAGCCACCCCTCCCAGGTTGGTGCTCACAGCCCCTCCCTGGCCCACTCCCTGCACACCTGCACCTGCTGGTCTCTGGGAGAGGAGCATCCATCCATCTTGTGCGCATAGCTTTCGGCTCCATTTTCATGAGGATGGTCTCCTTGGCAGAAATGCCCATTAGGGGATCCTGAGCCTGTGCTAGCTCTTCTCTAAGTGCCAAAGCCAGTGAGAGGGACTTGAAAACTCAAGACTTATTAACAGTATTTTCTGCATTTTGTGCTTTCAGGGTTGTTTTTTCCTTAAAATGTGTAAAAACAAACATTGAGATTTCTATCTTTTATATAATTTGGATTCTGTTATCACACGGACTTTTCCTGAAATTTATTTTTATGTATGTATATCAAACATTGAATTTCTGTTTTCTTCTTTACTGGAATTGTTAACTGTTTTATAGGCCAAATCTTTTAAAAAAAACACATCTCTCTAATTTCTCTAAACATTTCTAATTACATATATATTTACTATACCTAATACACTACTTTGGAATTCCTTGAGGCCTAAATGCATCGGGGTGCTCTGGTTTTGTTGTTGTTATTTCTGAATGACATTTACTTTGGTGCTCTTTATTTTGCGTATTTAAAACTATTAGATCGTGTGATTATATTTGACAGGTCTTAATTGACGCGCTGTTCAGCCCTTTGAGTTCGGTTGAGTTTTGGGTTGGAGAATTTTCTTCCACAAGGGATTGTCTTGGATTTTTCTGTTTCTCCCTCAATATCCACCTGGAAAACATTTCAATTAATTTATATTTACTTAAATATTTCTGTGCAAAAACTGTGTACAAAAGCCCCAAAGCATAATTTGTGCAGTTGAGCGCATGTTCTGTTGTTCAGCATTTATGGTGGTTGGTAGTGGAAAAGATTTTTAGAATATGTGGATTTTCGGGATATTCCCAGAAGCCCAGATAGCGACACTTTACCTTTGGAGGAATTACTTCTCAGAATATTGCACACAATCAATCGCCTTTGGAAGGAGCATATATCCCCAGCAAAAGCTCTGGTTTTTTGAAGTCTGTATTGTGTGTTACTTCCAGGAGAATATGCAATGATGACAATGTTATTAGATGATTCAAATATGAAGTGCTGTTATGCCAAACAATGAATCTTTGTGTTATACATTATGCCTAACTATAAATCTTTGTGTTATACATTTTAATGTCATTGGAGAGTACTCCTGTCTTCTTGGCATTATTGATAATTAGATTCTAATTGCTAATAAGTCAGAAAAATTAGGAACACCAAATTTCAGTTGTCTCAAAAGCACTCCTCTTATTAAATTTGGATGTTTACCTTTATCACATCAAAAGAAATATTGTTAGAAAGGTGTTTAATGTTTTGCAGATGGATAGATTACTGTTATTAGTTCTCATTTCATTGTTAATTTTTAAAACCATAAGGTTGGAAGTATCAATATGCCTTTCAATATACCTTAGTGGAATTTATTAAATTTTCATGGATGTCCTTTAGGGGGTTCAGGAAGTTATTTCTATTGCTAGATTTCTGGAAGATTTATCAGGAATGAGTGTCAGACATTGTCAGACGTCCATTGAAATCATCATGGTCTTTTCCTTTATTCTATTAATATGATGTATTACACTGATTGATTTTTAAATTTGTATTGGTAGGATAATTCCACTTGGTTATATTGTCTAACTTTTTTCTAATTTTCTTTCATTTTTATTACAGATGAGGCCTCACTCTGTCACCCAGGTTGGGGTGGAGTGGCACAGTCACAGCTCACTATAACCTCAAGCTCCTGGGCTCAAGTGATCCTGCCACCTCAGCCTCCTAAGTAGCTGGAACTACAGATGTGCACTGCCATGCCAGGCTTGTCTAACATTTTTATGTGTTGCTTCATCCAGTTTGCTAGAGTTTTTGGAGATTTCTGTCTTCATTCATGAGGGATAATAGTCTGCACTTTTATTTTCTTGTGATACTTTTGTCTGATTTGTTATCTGGGTAATACTGGCCTTGAAAATGAATTGATGTTTTCCTGCTTCTCTGCTTTGCAAGTGTTTGTGAAGGATTGGTTATTCATTAAGTGTTTAATAGAATTCACTAGTGAAGCTATGTGAGCCAGGGCTAGACTGATGAAGAGTTTTCATTAGTCTAATCTGTTTACTTGCTGTATAAGTACGCATATATTCTCTTTCTTCTTGATTTAATTTTACACTTTGTGTATAGCAGGGAATCTGTGTCTAATTTGTAGTATTTCATGCTTCTAGGTTTTCATGGCAGTTGAGATGTAAGAATAACAATAATGTTGGGAGAAGGAAGTTGTGGACAATCCATGAATATCCCAACATCTGTTGTAGGAAGGTTAAGATTACTTTTTTTTTTTTTGCTGTACTGAACTGAATACTCTTATTTATAATGTCAGACAAATGTAATGTTGTATATAAATAGAACTAGGAAAATGTGCCATTTGTCTTAGTATTTAATCAAGATGGAAGTCTGGGCCTACCTCCTCTCTTTTATTAATATGTAGACAGGACACCAACACAAATTAGAATGAAGACAAACAAAATGTTAGCAAATGAAGAATGGTATCAATTGGTTAAAATGTGATGAAATAGAGTGGTGAATATTTACATAGAATCCATGATGTGTTAGGTGCTATTTCAAGCTATTTGCACATATAGTTTTAATACCAATGACGTTAAAATGTATAACACAAAGATTCATATAAATAAAAATTACAACATTGTAAATAATATTAGGTGACACTAAAACTGTCATAGAAATACACATTTATATAAAACATAAAGTAACATGAAGTATTAAATTTTAGAAACTTTGATTACTAATCAGATGAACAACTGATTAGCCTTTTTATCCAGTAAAAAAGGCATACATATTATTTTCAAATTCCAGAGACAAATATTTTAAATATTGAAGTTGAAGACCTAAAAATGTGTCACTGACCTCATGGAAGTAGATATTCACTAGGTGATATTTTCTAGGCTCTCTGAAATTATATCAGAAAAATGTGAATTAGAATATAACCCATAAATAATATCTGGCCACATACAAAGTAATTGAAGATCAATTTAAATGGCTATTGGATTAAGAAATAGGGACTGAGGTAAATTTGCAGTGTCAGGGAGGATCTAAGGAGGAAGCATTGACACTGGAGCCCAAGGACCTGGGATCACAGAACAGATTCTACCAGTGCTAACTTACTGCTCCACAGAAAACATCAATTCTGCTCATGCGCAGGTACAATTCATCAAGAAAGGAATTACAACTTCAGAAATGTGTTCAAAATATATCCATACTTTGACATATTAATGAAGTAATCACATTCTACACATAACTACTCCATATGGAATACTGGGGAGGAGGTGTTCCAAATAAAGAGACTGAGGATTTCTCATGAGAACTCAGTGTCTGCTAGAAAATATCTAAGTAAAATATTTTACTTATGTGGAAAGTGTGGATGTTTGTGCATCAAAAGTTTCAAGAATCCCTAAAATTTACAATGGAGATGAGGAGAAAATATCAGAATTTCCCAGCACCAGAAATAAGGCAAGAAAAAATTCAGAGGGGTTGTAAATGTGAAAAGCCAATGGCTGGTCACACAGCAACATTGATAACCTTGTGCCTGGACAACTAGAATAAATACATAAACATACACATTGAAAATATTTCCAATATTAGATCTCCCTCATGTGAGAACTAAATTATAAAGATTGAAGCATAGAAGAAAATAAGCTACCAGAATAAATTTGATTACACATAAATTTCTGATATTGAAACTGTCACAAATGTTTAAGTTGGTAGTGGAAGACAAAGGACATATAATCTTGGGAGTCCTAAGGCCCTGCCCACTGCCAGTCCCTCCACACTACTACAGCTGATGCTTTCTGGAAATCACCACCTCCTGGCAGGAGCCCAACCAGCACAAATATAGAGCATTAAACCACCAAAGCTAAGGAGGCTCACAGAGTCTATTGCACCCTTCACCACCTCCACTGGAACAGGCGCTGGTATCCATGGCTCAGAGACCCAAAGATGGTTCACATCACAGGGCTCTATGCAGACAACCCCCAGTACCAGCCCAAAGCCACGTAGACCTGCTGGGTGGCTAGACCCAGAAGAGAGACAACAATCAATGCACTTTGGCTTACAGGAAGCCATGCCCATAGGAAAAAGGGGAGAGTACTACGTCAAGGGAACACCCCGTGGGATGAAAGAGTCTGAACAACAGTCTTCAGCCCTAGACCTTTCCTCTGACAGAGTCTACCAAAATGAGAAGGAACCAGAAAACCAACCCTGGTAATCTGACAAAACAAGAATCTTCAACACCCCCCAAAAAATCACACCAGTTCATCACCAATGGATCCAAACAAAGAAGAAATCACTGATTCATCTAAAAAAAAATTCAGGTTAGTTATTAAGCTAATCAGGGAGGGGCCAGAGAAAGATGAAGCCCAATGCAAGAAAATCCAAAAAATGATACAATACGTGAAGGGAGAATTATTCAAGGAAATAGATAGCTTAAATAAAAAAATAAAAAATCAGGAAACTTTGGACGTACTTTTAGAAATGTGAAATGCTCTGGAAAGTCTCAGCAATAGAATTGAACAAGTAGAAGAAAGAAATTCAGAATTCGAAGACAAGGTCTTTGATTTAACCCAATCCAATAAAGACAAAGAAAAAAGAATAAGAAAATATGAGCAAAGTCTCCAAGGAGTCTGGCATTCTGTTAAATGATGAAACCTAACACTAATTGGTGTACCTGAGGAAGAAGTGAATTCTAAAAGCCAGGAAAACATATTTGGGAGAATAATCTAGGAAAACTTCCATGGCCTTGTGAGAGACCTAGACATCCAAATACAAGAACCACAAATAACACCTGGGAAATTCATCACAAAAAGATCTTAGCCTAGGCACATTGTCATTAGGTTATCCAAAGTTAAGACAAAGGAAAGAATCTTAAGAGCTGTGAGACAGAAGCACTAGGTAACCTATAAAGGAAAACCTGTCAAATTAACAGCAGATTTCACAGCAGGAACCTTACAAGCTAGATGGGATTGGGGCCCTTTCTTCAGCCTCCTCAAACAAAACAATTATCAGCCAAGAATTTTGTATCCAGCAAAACTAAACATCATATATGAAGGAAAGATACAGTCATTTTCAGACAAACAAATGCTGACAGAATTTGCCATTACCAAGCCAGGACTCTAAGAACTGCTAAAAGGAGCTCTAAATCATGAAACAAATCCTGGAAACACATCAAAACAGAACTTCATTAACGCATAAATCACACAGGACCTATAAAACAAAAATACAAGTTAAAAAACAAAAACAAAGTACAGAGGCAACAAAGAGCATGATGAAAGCAATGGTACCTCACTTTTTAATACTAATGTTGGTTGTAAATGGCTTAAATGCTCCACTTACAAGATACAGAACCACAGAATGGATAACAACTCACCAACTAACTATCTGCTGCCTTCAGGAGACTCACCTAACACATAACGACTTACATAAACTTAAGGAAAGTGGTAGAAAAAGGCATTTCATGCAAATGGACACCAAAAGCAAGCAGCAGTAACTATTCTCATATGAGACAAAACAAACTTTAAAGCAACAGTAGCTAAAAGAGACAAAGAGAGACAGTATATCATCTGTCACCTGACAGTCTCATCCAACAGAAAAATATGACAATCCTAAACATATGTGAACCTAACACTGGAGCTCCCAAATTTATAAAACAATTACTAGTAGACATAAGAAATAAGATAGACAGCAACACAATAATAGTGGGGGACTTCAATACTCCACTGACAGCACTAGACAGGTCATCAAGACAGAAAGTCAACAAAGAAACAATGGATTTAAACTATACTTTGGAACAAATGGACTTAACAGATATATATAGAACATTTCATCCAACAACCACAGAATACACATTCTATTCAACAGCACATGGAATTTTCTCCAAGATAGACCATATGATAGGCCATAAAATGAGTCTCAATAAATTTAAGAAAATTGAAATTGTATCACGCACTCTCTCACATCACAATGGAATAAAACTGAAAATCAACTCCAAAAGGAATCTTCGAAACCATGCAAATACATGGAAATTAAATAACCTGCTCCTGAATGAGCATTGGGTGAAAAACGAAATCAAGATGGAAATGTAAAAAATTTCTTCGAACTGGATGACACAACCTATCAAGACCTCTGGGATACAGCAAAGGCAGTGCTAAGAGGAAAGTTTATAGCACTAAACACCTACGTCGAAAAGTCTGAAAGAGCACAGACAATCTAAGTTCACATCTCAGGGAACTAGAGAAGGAGGAACAAGCCAAACCCAATCCCAGCAAACAAAGGAAATAACCAAGATCAGAGCAGAACTAAATGAAATTGACACAACAACAACAACAACAAAAATACAAAACATAAATAAAACAAAAATTTGGTTATTTGAAAAGATA' 

def findStopCodon(dnaStr, startIndex, stopCodon): 
    currIndex = dnaStr.index(stopCodon, startIndex+3) 
    while (currIndex != -1): 
     diff = currIndex - startIndex 
     if (diff % 3 == 0): 
      return currIndex 
     else: 
      currIndex = dnaStr.index(stopCodon, currIndex+1) 
    return -1 

def findGene(dna, where): 
    startIndex = dna.index('ATG', where) 
    if startIndex == -1: 
     return '' 
    taa_index = findStopCodon(dna, startIndex, 'TAA') 
    tag_index = findStopCodon(dna, startIndex, 'TAG') 
    tga_index = findStopCodon(dna, startIndex, 'TGA') 
    minIndex = 0 
    if (taa_index == -1 | (tga_index != -1 & tga_index < taa_index)): 
     minIndex = tga_index 
    else: 
     minIndex = taa_index 
    if (minIndex == -1 | (tag_index != -1 & tag_index < minIndex)): 
     minIndex = tag_index 
    if minIndex == -1: 
     return "" 
    return dna[startIndex:minIndex + 3] 

def printAllGenes(dna): 
    startIndex = 0 

    while True: 
     currentGene = findGene(dna, startIndex) 
     if len(currentGene) == 0: 
      break 

     print(currentGene) 
     startIndex = dna.index(currentGene, startIndex) + len(currentGene) 

printAllGenes(gene_sequence) 

これは29個の遺伝子を出力し、どのくらいのものが見つかるかわかりません。下の行のエラーは、ストランドの残りの部分を通過する前に終了させて​​います。

あなたが部分文字列を見つけるために失敗した場合に .index()リターン -1という間違った印象の下にあるように見える

currIndex = dnaStr.index(stopCodon, currIndex+1) 

Answer 1

：これはそうではありません

currIndex = dnaStr.index(stopCodon, startIndex+3) 
while (currIndex != -1): 

が、それは代わりにエラーがスローされます。

>>> help(str.index) 
Help on method_descriptor: 

index(...) 
    S.index(sub[, start[, end]]) -> int 

    Like S.find() but raise ValueError when the substring is not found. 

>>> 

ヘルプの説明には、実際には.find()メソッドが必要です。

はのは、単にあなたのコードにしてみてくださいだけでなく、それにパッチを適用してみましょう：

gene_sequence = 'AAC...ATA' # supply your original sequence here 

STOP_CODONS = {'TAA', 'TAG', 'TGA'} 

def findStopCodon(dnaStr, startIndex, stopCodons): 

    for currIndex in range(startIndex + 3, len(dnaStr), 3): 
     if dnaStr[currIndex:currIndex + 3] in stopCodons: 
      return currIndex 

    return -1 

def findGene(dna, where): 
    startIndex = dna.find('ATG', where) 

    if startIndex == -1: 
     return '', startIndex 

    stopIndex = findStopCodon(dna, startIndex, STOP_CODONS) 

    if stopIndex == -1: 
     return '', stopIndex 

    return dna[startIndex:stopIndex + 3], stopIndex + 3 

def printAllGenes(dna): 
    startIndex = 0 

    while True: 
     currentGene, startIndex = findGene(dna, startIndex) 

     if not currentGene: # empty strings are False 
      break 

     print(currentGene) 

printAllGenes(gene_sequence) 

これは69個の遺伝子を出力し、中断されません。それが実際にあなたが望むことを確かめるためにそれをテストしてください。