合胞素-2(英語:Syncytin-2,也稱為內源性逆轉錄病毒FRD組成員1,endogenous retrovirus group FRD member 1),它由ERVFRD-1基因編碼[5],與胚胎在子宮中的着床有關[6]。該基因是一種內源性病毒元件,它是約4500萬年前逆轉錄病毒感染人類後的殘餘物[7]。
ERVFRD-1;, ERVFRDE1, GLLL6191, HERV-FRD, HERV-W/FRD, UNQ6191, envFRD, endogenous retrovirus group FRD member 1, endogenous retrovirus group FRD member 1, envelope
^Vargas A, Moreau J, Landry S, LeBellego F, Toufaily C, Rassart E, Lafond J, Barbeau B. Syncytin-2 plays an important role in the fusion of human trophoblast cells. Journal of Molecular Biology. 2009, 392 (2): 301–18. PMID 19616006. doi:10.1016/j.jmb.2009.07.025.