Table 1. Genomic structure of amphibian and fish FLERVs.

Class	Species	Gene*
		gag	pol	acc3	acc4	env	Accessory gene (acc)
							acc1	acc2
Amphibia	Cynops pyrrhogaster	○	○			○	○†
		○	○			○	○†
	Hynobius retardatus	○	○			○
	Lissotriton vulgaris	○
	Notophthalmus viridescens	○	○			○	○†
	Pleurodeles waltl	○	○			○	○†
	Xenopus tropicalis		○
Chondrichthyes	Callorhinchus milii		○
Osteichthyes	Amphilophus citrinellus		○
		○	○	○	○	○	○‡	○
	Anoplopoma fimbria	○	○	○		○		○
			○
	Austrofundulus limnaeus	○	○	○		○	○	○
	Cynoglossus semilaevis	○	○	○		○	○
	Cyprinus carpio		○
	Dicentrarchus labrax	○	○	○	○		○	○
	Esox lucius		○
	Fundulus heteroclitus	○	○	○		○	○
	Gadus morhua	○	○	○	○	○
			○
	Larimichthys crocea	○	○	○	○	○	○	○
	Lates calcarifer	○	○	○	○	○	○	○
	Nothobranchius furzeri		○			○
	Oreochromis niloticus	○	○	○	○		○
	Periophthalmodon schlosseri		○
	Periophthalmus magnuspinnatus		○
	Pimephales promelas		○
		○	○			○
	Poecilia formosa	○	○	○	○	○	○
		○	○	○	○	○	○
	Poecilia reticulate	○	○	○	○	○	○
	Sebastes nigrocinctus		○				○
	Sebastes rubrivinctus		○				○
	Stegastes partitus	○	○	○	○	○	○	○
	Thunnus orientalis		○			○
Sarcopterygii	Latimeria menadoensis	○	○			○

^*Open circles ‘○’ indicate the presence of the gene. When there is more than one FLREV lineage in a genome, their genomic structures were annotated separately. NviFLERV, AciFLERV, AliFLERV, CoeEFV and DrFV-1 protein sequences were used as probes.

^†We identified only one accessory gene (acc) in salamander FLERVs (see also Fig. 2); therefore it is unclear whether it is acc1 or acc2.

^‡Two copies of acc1 genes were found in the FLERV, annotated as acc1a and acc1b (see Fig. 2).