def locusTotals(vASVDF):
    """
    Takes a vASV locus summary df and return with colum 'total' which
    represents the sum of counts for each locus.
    :param vASVDF: vASV summary df
    :return: updated vASV summary df with 'total' column
    """
    vASVDF['total'] = vASVDF['count'].groupby(vASVDF['locus']).transform('sum')
    return vASVDF