据2月10日的《科学 - 转化医学》杂志内一项新的基因学研究报告说，HIV是以RNA的形式通过精液在发生性关系的男性-男性之间进行传播的。 这些发现查到了HIV传播的根源，回答了HIV在男性之间是如何传播的这一根本问题，并可能帮助人们将精力聚焦在如何以疫苗、阴道微生物杀灭剂或药物的形式研发成功的预防HIV的方法。
据世界卫生组织（World Health Organization1）披露，全球大约有3300万人感染了HIV。 在这项研究中，David Butler及其同僚通过收集血液和精液样本对6对男性（[源始性伴]，即他们通过与其它的男性[接受方性伴]发生性关系而将其HIV传播给这些接受方性伙伴）的血液和精液中的HIV进行了基因测序研究。 精液是由精子、白细胞以及包裹这些细胞的叫做精浆的液体所组成的。
HIV病毒颗粒中含有自由流动的RNA，它们存在于精浆中，而精液中的白细胞则含有HIV的DNA – 这两者都可以是具有高度传染性的感染源。研究人员检查了在每一源始性伴以及每位接受方性伴精浆及白细胞中所发现的HIV的基因学特征，并对其进行了系统发生学的分析；这是一种通过比较基因学特征来确定生物相关性方法（非常类似用系谱图的方法来检视每个个体或动物标本之间相互关系的亲疏）。通过构建一种有关这些病毒的“系谱图”，研究人员能够追溯这些病毒的先祖史。他们得出结论，这些HIV来自源始性伴精浆中的RNA（而非他们白细胞中的DNA）。
The Origins of Sexually Transmitted HIV Among Men Who Have Sex with Men
Although it is known that most HIV-1 infections worldwide result from exposure to virus in semen, it has not yet been established whether transmitted strains originate as RNA virions in seminal plasma or as integrated proviral DNA in infected seminal leukocytes. We present phylogenetic evidence that among six transmitting pairs of men who have sex with men, blood plasma virus in the recipient is consistently more closely related to the seminal plasma virus in the source. All sequences were subtype B, and the env C2V3 of transmitted variants tended to have higher mean isoelectric points, contain potential N-linked glycosylation sites, and favor CCR5 co-receptor usage. A statistically robust phylogenetically corrected analysis did not detect genetic signatures reliably associated with transmission, but further investigation of larger samples of transmitting pairs holds promise for determining which structural and genetic features of viral genomes are associated with transmission.
