def createGeneToAabrhD(aabrhHardCoreL):
    """Create a dict where key corresponds to gene number and the
value at that location is the number of the aabrh group to which the
gene belongs. The aabrh groups are numbered, simply based on
the index where they occur in aabrhHardCoreL."""
    geneToAabrhD = {}
    for aabrhNum in range(len(aabrhHardCoreL)):
        for geneNum in aabrhHardCoreL[aabrhNum]:
            geneToAabrhD[geneNum] = aabrhNum
    return geneToAabrhD
