Problem B. DNA: Codon Segmenting The way that DNA is often interpreted as genes is in groups of three nucleotides at a time, called “codons.” Thus, the DNA strand dna_str = 'agctttcattctgac' Can be broken into codons in the following three ways: agc ttt cat tct gac a gct ttc att ctg ac ag ctt tca ttc tga c # reading frame 0 # reading frame 1 # reading frame 2 Notice that in these lines, we start reading codons at string indexes 0, 1 and 2. The three different start indices are known as reading frames, and are called reading frame 0, reading frame 1 and reading frame 2, respectively. It is not always clear which of these frames will be read by genetic transcription mechanisms, so it is often useful to be able to be flexible and consider any of them when working with DNA strands. Write a function segment that takes as an input a string containing a DNA strand, and a reading frame (0, 1 or 2) to use. The function should return a list containing the sequence of individual codons. You can assume that the dna string will be properly formatted: that is, it is entirely lowercase and consists only of the letters ‘a’, ‘t’, ‘c’, and ‘g’. You may also assume that there will be at least three characters in the given dna string. Examples: >>> segment('ttgttgtttg', 0) ['ttg', 'ttg', 'ttt', 'g'] >>> segment('ttgttgtttg', 1) ['t', 'tgt', 'tgt', 'ttg'] >>> segment('ttgttgtttg', 2) ['tt', 'gtt', 'gtt', 'tg'] >>> segment('agctttcattctgac', 1) ['a', 'gct', 'ttc', 'att', 'ctg', 'ac']
Problem B. DNA: Codon Segmenting
The way that DNA is often interpreted as genes is in groups of three
Can be broken into codons in the following three ways:
Notice that in these lines, we start reading codons at string indexes 0, 1 and 2. The three different start indices are known as reading frames, and are called reading frame 0, reading frame 1 and reading frame 2, respectively. It is not always clear which of these frames will be read by genetic transcription mechanisms, so it is often useful to be able to be flexible and consider any of them when working with DNA strands.
Write a function segment that takes as an input a string containing a DNA strand, and a reading frame (0, 1 or 2) to use. The function should return a list containing the sequence of individual codons.
You can assume that the dna string will be properly formatted: that is, it is entirely lowercase and consists only of the letters ‘a’, ‘t’, ‘c’, and ‘g’. You may also assume that there will be at least three characters in the given dna string.
Examples:
>>> segment('ttgttgtttg', 0) ['ttg', 'ttg', 'ttt', 'g'] >>> segment('ttgttgtttg', 1) ['t', 'tgt', 'tgt', 'ttg'] >>> segment('ttgttgtttg', 2) ['tt', 'gtt', 'gtt', 'tg'] >>> segment('agctttcattctgac', 1) ['a', 'gct', 'ttc', 'att', 'ctg', 'ac']
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