# Description
When considering a set of aligned sequences, identical character states can be [homoplasitc](https://en.wikipedia.org/wiki/Homoplasy) (_i.e._ convergent evolution), or [synapomorphic](https://en.wikipedia.org/wiki/Synapomorphy_and_apomorphy) (acquired by descent).
This script aims at finding shared character states inside a multiple sequences alignment irrespective of the evolution of the sequences.
It takes as input a fasta file containing aligned sequences, and a list of sequences whose name match those in the alignment.
The output is a list of the shared character states followed by an entropy score - the closest is the score to 1, the more the result is significant.
If the sequences you gave as parameters share a common ancestor, then the output are synapomorphies. Otherwise they are homoplasies.

# Installation
This script is written in Bash and as such should run on any Unix platform.
Simply download the file, navigate to its location and then type

```bash
chmod +x find_synapomorphies.sh
```

# Usage

```bash
./find_synapomorphies.sh "seq1,seq2,seq3" <input_file> <output_file>
```

* the input file is a fasta file containing a multiple sequences alignment
* the sequences of interest are comma-separated and inside a pair of double quotes

# Example

```bash
./find_synapomorphies.sh "seq1,seq2" example.fasta example.output
```