Table 2.

Loss of heterozygous Nfia⁻ progeny from heterozygous Nfia⁻ mothers

Progeny	Number of progeny with genotype
	Heterozygous Nfia− male × WT female		Heterozygous Nfia− female × WT male
	+/+	−/+	+/+	−/+
Male	60	46	33	26
Female	41	40	35	13
Total	101	86	68	39*
(Expected)	(101)	(101)	(68)	(68)

Heterozygous Nfia⁻ males were crossed with wild-type (WT) females and heterozygous Nfia⁻ females were crossed with wild-type males. The genotype and sex of the progeny of the different crosses were recorded. All animals were in the outbred Black Swiss background. The reduction in the total number of heterozygous Nfia⁻ animals compared to expected in the latter cross is significant (∗, P < 0.01 by χ²) and may be caused by preferential loss of heterozygous female progeny.