def _collate_parents(parent1, parent2):
    """Collect the columns and metadata from each parent together. These lists
    form a pool from which information is inherited during the crossover
    process."""

    parent_cols, parent_meta = [], []
    for dataframe, metadata in [parent1, parent2]:
        parent_cols += [dataframe[col] for col in dataframe.columns]
        parent_meta += metadata

    return parent_cols, parent_meta