Table 1. Comparison between wild-type (loxP) and mutant lox spacer regions.

lox site	Spacer sequence	Incompatible with
loxP	GCATACAT	m2, m3, m7, m11
lox511	GtATACAT	Not tested
m2	tggTttcT	loxP
m3	tggTAtta	loxP, m7
m7	ttcTAtcT	loxP, m3
m11	tggTAtcg	loxP

Lower case letters indicate nucleotides that differ from the loxP spacer sequence.