def combine_gene_pos(hybridizations_infos, converted_positions, hybridization):
    """
    Gather info about the imaging at each hybridization.

    This function creates a dictionary where for each hybridization
    are shown the genes and number of positions imaged for each
    gene. This function will be useful to created distribution lists
    for running parallel processing of the datasets.

    Parameters:
    -----------

    hybridizations_infos: dict
        Dictionary with parsed Hybridizations metadata
    converted_positions: dict 
        Dictionary with the coords of the images for all hybridization. 
        The coords are a list of floats
    hybridization: str
        Selected hybridization to process

    Returns:
    -----------

    genes_and_positions: dict 
        Dictionary where for each hybridization, the genes and number of 
        positions imaged for each gene are showed.
    """
    genes_and_positions = dict()
    for gene in hybridizations_infos[hybridization].keys():
        genes_and_positions[gene] = list(converted_positions[hybridization]
            .keys())
    return genes_and_positions
