def reverse_complement_no_loops(seq):
    """Return WC complement of a base without loops"""
    # Initialize rev_seq to a lowercase seq
    rev_seq = seq.lower()
    # Substitute bases
    rev_seq = rev_seq.replace('t','A')
    rev_seq = rev_seq.replace('a','T')
    rev_seq = rev_seq.replace('g','C')
    rev_seq = rev_seq.replace('c','G')

    return rev_seq[::-1]