def get_pedigree_dict(interpretation_request):
    """Make a simple dictionary representation of the pedigree.

    Create a dictionary corresponding to relation_to_proband: gelId pairs.

    Args:
        interpretation_request: JSON representation of an
            interpretation_request (output of get_interpretation_request_json).

    Returns:
        pedigree: Dictionary of keys 'relation_to_proband' and 'gelId' pairs
            extracted from the interpretation_request object.
    """
    pedigree = {}
    for p in (interpretation_request['interpretation_request_data']
    ['interpretation_request_data']['json_request']['pedigree']
    ['participants']):
        if p['isProband']:
            pedigree['Proband'] = p['gelId']
        else:
            try:
                pedigree[p['additionalInformation']['relation_to_proband']] = (
                    p['gelId'])
            except KeyError:
                pass
    return pedigree