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73 lines
2.3 KiB
Markdown
73 lines
2.3 KiB
Markdown
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# Hamming
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Calculate the Hamming difference between two DNA strands.
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A mutation is simply a mistake that occurs during the creation or
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copying of a nucleic acid, in particular DNA. Because nucleic acids are
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vital to cellular functions, mutations tend to cause a ripple effect
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throughout the cell. Although mutations are technically mistakes, a very
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rare mutation may equip the cell with a beneficial attribute. In fact,
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the macro effects of evolution are attributable by the accumulated
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result of beneficial microscopic mutations over many generations.
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The simplest and most common type of nucleic acid mutation is a point
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mutation, which replaces one base with another at a single nucleotide.
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By counting the number of differences between two homologous DNA strands
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taken from different genomes with a common ancestor, we get a measure of
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the minimum number of point mutations that could have occurred on the
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evolutionary path between the two strands.
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This is called the 'Hamming distance'.
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It is found by comparing two DNA strands and counting how many of the
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nucleotides are different from their equivalent in the other string.
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GAGCCTACTAACGGGAT
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CATCGTAATGACGGCCT
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^ ^ ^ ^ ^ ^^
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The Hamming distance between these two DNA strands is 7.
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# Implementation notes
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The Hamming distance is only defined for sequences of equal length. This means
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that based on the definition, each language could deal with getting sequences
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of equal length differently.
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## Elm Installation
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Refer to the [Exercism help page](http://exercism.io/languages/elm) for Elm
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installation and learning resources.
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## Writing the Code
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The first time you start an exercise, you'll need to ensure you have the
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appropriate dependencies installed.
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```bash
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$ npm install
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```
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Execute the tests with:
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```bash
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$ npm test
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```
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Automatically run tests again when you save changes:
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```bash
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$ npm run watch
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```
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As you work your way through the test suite, be sure to remove the `skip <|`
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calls from each test until you get them all passing!
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## Source
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The Calculating Point Mutations problem at Rosalind [http://rosalind.info/problems/hamm/](http://rosalind.info/problems/hamm/)
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## Submitting Incomplete Solutions
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It's possible to submit an incomplete solution so you can see how others have completed the exercise.
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