*******************************************************
           *                                                     *
           *     *********  * * *          *       *********     *
           *     *          *     *       * *          *         *
           *     *******    *  * *       *   *         *         *
           *     *          *     *     * *** *        *         *
           *     *          *     *    *       *       *         *
           *     *          * * *     *         *      *         *
           *                                                     *
           *          Xin Xu  C1999-2009       v2.0.4Q       *
           *          Program for Population Genetics            *
           *          Harvard School of Public Health            *
           *                                                     *
           *******************************************************