Table 1.

Characterization of HPRT-positive YAC clones by PCR

YAC isolate	Size, kb	Exons present
		1	2	3	4	5	6	7+8*	9
1	80	+	+	+	+	+	+	+	+
2	100	+	+	+	+	+	+	+	+
3	120, 300†	+	+	+	+	+	+	+	+
4	140, 250, 600†	+	+	+	+	+	+	+	+
5	55	−	+	+	+	+	+	+	+
6	55	−	+	+	+	+	+	+	+
7	ND	−	+	−	−	−	+	+	+

ND, not determined. 

^*The primers amplify exon 7 and exon 8 sequences along with short sequences of flanking introns (12). 

^†The colony consists of a mixture of cells with different size YACs. All YACs contain the entire HPRT gene.