def coverage_shortest(seq_query, seq_target, seq_len):
    """
    Return coverage of the shortest sequence in the alignment.

    >>> coverage_shortest("AAAA----", "AAAAAAAA", 8)
    50.0
    """
    res_query = len(seq_query.replace('-', ''))
    res_target = len(seq_target.replace('-', ''))
    return 100.0 * min(res_query, res_target) / seq_len