Table 1.

Average number of PH3-positive cells in organ-forming endoderm

	hpf	24	28	32	48
Siblings	Av.	2.63	4.79	5.30	6.50
	s.d.	1.82	2.25	2.39	4.23
	N	16	19	20	10
hdac1−/−	Av.	2.17	3.75	2.77	3.64
	s.d.	1.20	2.29	1.88	2.73
	N	18	9	13	11

Av. Average, s.d. standard deviation, N number of embryos, hpf hours post-fertilisation.

Proliferation rates are reduced in the organ-forming endoderm in hdac1 mutants between 24 and 48 hpf.