def getProximityInWindow(geneWinT, geneProximityD):
    """Given a window of genes, calculate the distances between first gene
and the rest (in number of genes) and store in geneProximityD. Updates
geneProximityD in place, returning None.
    """
    gnA = geneWinT[0]
    for i in range(1, len(geneWinT)):
        gnB = geneWinT[i]
        if gnA < gnB:
            geneProximityD[gnA, gnB] = i
        else:
            geneProximityD[gnB, gnA] = i
