def read_genome_dir_file(genome_dir_file):
    """Read genome directories from file.

    Parameters
    ----------
    genome_dir_file : str
        File to read.

    Returns
    -------
    dict : d[genome_id] -> directory
        Directory for each genome.
    """
    genome_dirs = {}
    for line in open(genome_dir_file):
        line_split = line.split('\t')
        genome_dirs[line_split[0]] = line_split[1].strip()
    return genome_dirs
