# Hamming

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'.

It is found by comparing two DNA strands and counting how many of the
nucleotides are different from their equivalent in the other string.

    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. This means
that based on the definition, each language could deal with getting sequences
of equal length differently.

## Resources

Remember to check out the Perl 6 [documentation](https://docs.perl6.org/) and
[resources](https://perl6.org/resources/) pages for information, tips, and
examples if you get stuck.

## Running the tests

There is a test suite and module included with the exercise.
The test suite (a file with the extension `.t`) will attempt to run routines
from the module (a file with the extension `.pm6`).
Add/modify routines in the module so that the tests will pass! You can view the
test data by executing the command `perl6 --doc *.t` (\* being the name of the
test suite), and run the test suite for the exercise by executing the command
`prove . --exec=perl6` in the exercise directory.
You can also add the `-v` flag e.g. `prove . --exec=perl6 -v` to display all
tests, including any optional tests marked as 'TODO'.

## 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.