Table 1. General properties of the overlapping gene dataset.

Nature of the genome	Number of familiesa	Number of generaa and species (in parentheses)	Number of overlapping gene pairsb	Number of proteins affected by overlapc
ssRNA+	16	24 (26)	37	70
ssRNA-	6	12 (13)	15	29
ssDNA	3	9 (9)	14	26
dsRNA	2	5 (5)	5	10
dsDNA	1	1 (1)	1	2
ssRNA-RT	1	3 (6)	6	12
dsDNA-RT	1	1 (1)	2	3
Total	30	55 (61)	80	152

^aUnassigned genera or unassigned families are counted as bona fide genera or families

^bSome genera contain several overlapping gene pairs

^cSome genes overlap with more than one gene