def load_core_file(core_fp):
    """
    For core OTU data file, returns Genus-species identifier for each data
    entry.
    :type core_fp: str
    :param core_fp: A file containing core OTU data.
    :rtype: str
    :return: Returns genus-species identifier based on identified taxonomical
             level.
    """
    core = {}
    with open(core_fp) as in_f:
        for line in in_f.read().splitlines():
            if not line.startswith("#"):
                otu_id, tax = line.split("\t")
                core[otu_id] = oc.otu_name(ast.literal_eval(tax))
    return core