def get_clone(rec):
    """
    >>> get_clone("Medicago truncatula chromosome 2 clone mth2-48e18")
    ('2', 'mth2-48e18')
    """
    s = rec.description
    chr = re.search(chr_pat, s)
    clone = re.search(clone_pat, s)
    chr = chr.group(1) if chr else ""
    clone = clone.group(1) if clone else ""

    return chr, clone