TABLE 1.
Distribution of known betaretroviruses
| Betaretrovirus(es) | Endogenous (En) and/or exogenous (Ex) | Known host(s) | Prehistoric distribution of host(s) | Time of entry into genome of hosta |
|---|---|---|---|---|
| MMTV | En, Ex | Rodents within Mus genus | Africa, Europe, Asia, Southeast Asia | Recent (7,14) |
| JSRV and ENTV | En, Ex | Sheep, goats | Northeast Africa, Southern Europe, Asia | >4-10 MYA (12) |
| SMRV | En | Squirrel monkey (New World) | South America | Recent? (8) |
| TvERV-D | En | Common brushtail possum | Australia | ? (1) |
| MusD | En | Rodents within Mus genus | Africa, Europe, Asia, Southeast Asia | >1-2 MYA? (18) |
| SERV | En | Old World monkeys | Africa, Asia | <9 MYA (32) |
| MPMV, SRV-1, and SRV-2 | Ex | Old World monkeys | Africa, Asia | N/A |
a
?, time of entry into genome is unknown; N/A, not applicable because retrovirus is exogenous; MYA, million years ago. References are shown in parentheses.