Table 1.

Genotype frequency in 3 week old B6 × BALB F2 CF and non-CF mice

	Marker	Position (Mb)a	No. mice	No. B6:B6	No. B6:BALB	No. BALB:BALB	P-valueb
F2 Non-CF 3 weeks
Females	D5Mit239	107.7	707	145	292	270	5.7 × 10-15
	DXMit16	95.6	687	210	188	289	3.0 × 10-35
	D3Mit189	101.1	367	101	171	95	0.39
Males	D5Mit239	107.7	358	74	192	92	0.16
	DXMit16	95.6	341	154c	0	187	0.07
	D3Mit189	101.1	364	98	176	90	0.69
F2 CF 3 weeks
Females	D5Mit239	107.7	58	9	30	19	0.17
	DXMit16	95.6	56	14	31	11	0.62
	D3Mit189	101.1	54	16	23	15	0.54
Males	D5Mit239	107.7	75	9	45	20	0.035
	DXMit16	95.6	79	35	0	43	0.37
	D3Mit189	101.1	75	15	40	20	0.61

^ataken from the Ensembl database, release 40, August 2006.

^bP-values obtained by standard Pearson's χ² test comparing observed values to expected 1:2:1 ratio (B6/B6:B6/BALB:BALB/BALB) of genotypes (except for 1:1 X chromosome genotypes of male mice). B6 = C57BL/6J, BALB = BALB/cJ.

^c DXMit16 genotype is B6 or BALB in male mice.