Table 2.

Effect of Pax-2 and Pax-5 dosage on prenatal brain morphology in the C57BL/6 strain

Mouse strain c57/Bl6	Brain morphology	Number of animals (n = 116)
Wild type	“Normal”	9
		(approx. 1/16)
Pax-2 −/−	“Normal”	7
	(30% exenceph.)	(approx. 1/16)
Pax-5 −/−	“Normal”	8
		(approx. 1/16)
Pax-2 +/−	“Normal”	33
Pax-5 +/−		(approx. 1/4)
Pax-2 +/+	“Normal”	12
Pax-5 +/−		(approx. 1/8)
Pax-2 +/−	“Normal”	14
Pax-5 +/+		(approx. 1/8)
Pax-2 +/−	“Normal”	14
Pax-5 −/−		(approx. 1/8)
Pax-2 −/−	Altered	11
Pax-5 +/−		(approx. 1/8)
Pax-2 −/−	Altered	8
Pax-5 −/−		(approx. 1/16)

Brain morphology was analyzed on histological sections of embryos of different ages stained with cresyl violet (Nissl method). Phenotypes showing no morphological alteration, or only subtle morphological alteration were scored as “normal.” Only major anatomical alterations, as the ones reported in this study (see text) were scored as “altered.” The Pax-5 homozygous mouse showed minor changes in the inferior colliculus and in the cerebellar foliation pattern only apparent at late stages of development, as reported (3), and therefore was entered in this table as “normal.”