TABLE 4

Trap type predicted by insertion site position relative to genes

Screen	Independent insertions	% lethal	Protein	Protein?^a	Enhancer	Enhancer opposite	No gene
G	82	ND	55	0	9	9	9
ZCL	139	ND	93	2	12	22	10
P	60	ND	19	1	19	11	10
YB	159	33	36	1	54	46	22
YC	65	30	43	3	8	7	4
YD	314	47	49	10	152	30	73
Total	819		295	17	254	125	128
Genes	335		115	4	136	82	NA

↵a Examination of these insertions showed the potential for splicing the GFP exon to the first exon of a gene and maintaining an open reading frame. RNA analysis on these lines is needed to assign them to protein or enhancer trap designations.