def get_individuals(filename):
    """
    Returns a list of all the different individuals contained in the file.
    :param filename:
    :return:
    """
    f = open(filename)
    
    individuals = set()
    
    for line in f:
        
        if "//" in line:
            continue
        
        (individual, sequence) = line[1:].split()
        individuals.add(individual)
        
    return list(individuals)