Table 1.

Classification of human endogenous retroviruses (HERVs). HERVs are grouped into three classes, based on similarity to the exogenous Gammaretrovirus, Betaretrovirus and Spumavirus, respectively.

Class	Family	Subgroups
Class I	HERV-H, HERV-F, HERV-W, HERV-R, HERV-P, HERV-E, HERV-I, HERV-T, ERV-FTD, ERV-FRD
Class II	HERV-K	HML 1-11
Class III	HERV-L