# Point Mutations

Calculate the Hamming difference between two DNA strands.

A mutation is simply a mistake that occurs during the creation or
copying of a nucleic acid, in particular DNA. Because nucleic acids are
vital to cellular functions, mutations tend to cause a ripple effect
throughout the cell. Although mutations are technically mistakes, a very
rare mutation may equip the cell with a beneficial attribute. In fact,
the macro effects of evolution are attributable by the accumulated
result of beneficial microscopic mutations over many generations.

The simplest and most common type of nucleic acid mutation is a point
mutation, which replaces one base with another at a single nucleotide.

By counting the number of differences between two homologous DNA strands
taken from different genomes with a common ancestor, we get a measure of
the minimum number of point mutations that could have occurred on the
evolutionary path between the two strands.

This is called the 'Hamming distance'

    GAGCCTACTAACGGGAT
    CATCGTAATGACGGCCT
    ^ ^ ^  ^ ^    ^^

The Hamming distance between these two DNA strands is 7.

# Implementation notes

The Hamming distance is only defined for sequences of equal length. Hence you
may assume that only sequences of equal length will be passed to your hamming
distance function.

**Note: This problem is deprecated, replaced by the one called `hamming`.**

## Exception messages

Sometimes it is necessary to raise an exception. When you do this, you should include a meaningful error message to
indicate what the source of the error is. This makes your code more readable and helps significantly with debugging. Not
every exercise will require you to raise an exception, but for those that do, the tests will only pass if you include
a message.

To raise a message with an exception, just write it as an argument to the exception type. For example, instead of
`raise Exception`, you shold write:

```python
raise Exception("Meaningful message indicating the source of the error")
```

## Submitting Exercises

Note that, when trying to submit an exercise, make sure the solution is in the `$EXERCISM_WORKSPACE/python/point-mutations` directory.

You can find your Exercism workspace by running `exercism debug` and looking for the line that starts with `Workspace`.

For more detailed information about running tests, code style and linting,
please see the [help page](http://exercism.io/languages/python).

## Source

The Calculating Point Mutations problem at Rosalind [http://rosalind.info/problems/hamm/](http://rosalind.info/problems/hamm/)

## Submitting Incomplete Solutions
It's possible to submit an incomplete solution so you can see how others have completed the exercise.