TABLE 2.

Frequencies of HeT-A additions and terminal gene conversions in the y^TD/y¹ lines^a

Generation	Su(var)2-5 mutation	Total no. of flies scored	Gene conversionb		DNA attachmentb
			No.	% Q	No.	% Q
F1	Su(var)2-5+	4,522	12	0.27	2	0.04
	Su(var)2-502	3,067	14	0.45	1	0.03
	Su(var)2-504	1,290	3	0.23	0	<0.07
	Su(var)2-505	2,175	10	0.45	1	0.05
F2	Su(var)2-5+	3,821	15	0.40	1	0.03
	Su(var)2-502	1,246	3	0.24	162	13
	Su(var)2-504	1,548	1	0.06	375	24
	Su(var)2-505	1,266	2	0.16	243	20
F3	Su(var)2-5+	2,484	18	0.72	0	<0.04
	Su(var)2-502	648	2	0.31	102	15
	Su(var)2-504	984	1	0.10	162	16
	Su(var)2-505	1,690	2	0.12	281	17

^aThe scheme of crosses is shown in Fig. 2.

^bAbbreviations: No., total number of flies displaying a new y phenotype that is generated either by DNA elongation via gene conversion or by attachment of the telomere-specific mobile elements; Q, average frequency of visible events signifying a new y phenotype versus total number of flies scored (in percent).