def get_chromosome_names_in_GTF(options):
    """ Function to get the list of chromosome names present in the provided GTF file. """
    chr_list = []
    with open(options.annotation, "r") as GTF_file:
        for line in GTF_file:
            if not line.startswith("#"):
                chr = line.split("\t")[0]
                if chr not in chr_list:
                    chr_list.append(chr)
    return sorted(chr_list)