So, I have a dataset which is of the format:
BBS1    Bbs1    reg 7   Heart
ASAP2   Asap2   reg 5   Heart
SPATA22 Spata22 reg 1   Heart
MYLK4   Mylk4   reg 1   Heart
ATP8A1  Atp8a1  reg 5   Heart
Now the organ name (here Heart) can be different. I there are several organs that the data is about. I am wondering how I can figure out the names of the unique elements of that column(column 5)? The data file is huge.