Summary of distribution of HIV-1 (env gp41, PR) and HIV-2 (PR and INT) gene sequences.

CRF, denotes circulating recombinant forms; * denotes gene regions where RT-PCR amplification was attempted; PR, protease; INT, denotes Integrase; gp41, envelope glycoprotein 41. Neg indicates no amplifiable PCR product.CRF即循环重组型（circulating recombinant forms）；* 代表尝试进行RT-PCR扩增的基因区域；PR为蛋白酶（protease），INT为整合酶（Integrase），gp41为包膜糖蛋白41（envelope glycoprotein 41）。Neg表示未获得可扩增的PCR产物。