Cdkn1c (p57 Kip2 ) is the major regulator of embryonic growth within its imprinted domain on mouse distal chromosome 7

Table 1 Contribution of transgenic ES cells to coat colour and germ line transmission in chimeras.

Line	Copy no.	Chimeras/total number born	% 129/Sv Coat colour	% Transmission 129/Sv coat colour
5D3	1	11/11 (5 d.e. pups died)	100	100
			100	100
			100	100
			100	100
			100	100
			100	100
5C2	1	10/10 (9 d.e died)	80	12.5
6C1	1	2/2 (one d.e. died)	100	100
5A4	2	6/6	100	100
			100	100
			100	100
			100	100
			30	100
			0	n.t.
5A2	2	7/8 (4 d.e. died)	100	100
			100	100
			100	N.t.
			30	n.t
5B6	4	4/9 (2 d.e died)	60	100%
			40 (female)	n.t.
5A6	4–8	0/8	-	-
6A3	4–8	0/9	-	-
5A3	4–8	0/5	-	-
6A4	4–8	0/0	-	-

129/Sv ES were aggregated with MF1 morula to generate chimaeric animals containing both ES cells (agouti) and the host MF1 cells (albino). The contribution of ES to the adult chimera was estimated by the percentage of agouti in the coat colour and found to decrease with increasing copy number. Additionally, 50% (21/40) of the pups with dark eyes (d.e.), indicating a strong contribution of ES cells, were born dead or die shortly after birth.
n.t. = not tested.

ISSN: 1471-213X