Table 1.

Compositions of different DNA types in euchromatic and heterochromatic regions of plant genomes.

	Approximate proportions (%)
	Tandem		DNA	Predicted	Predicted
Region	repeats*	Retroelements	transposons	genes	pseudogenes	[Ref]
Arabidopsis
183 kb central	25	30	15	[0 to 4]†		[4]
hk4S knob
Arabidopsis
520 kb hk4S	10	30	10	[1 to 25]†		[4]
knob
Arabidopsis	0 to 4	0 to 4	0 to 4	45 to 75	0 to 1	[5]
genic
Arabidopsis
'centromeric'	0 to >50	0 to 50	0 to 30	0 to 20	0 to 4	[5]
(II and IV)‡
Arabidopsis
pericentromeric	0 to 8	0 to 65	0 to 8	0 to 25	0 to 6	[5]
(II and IV)
Rice genic
(Adh 1/Adh 2)	0	14	14	26	4	[20]
Maize genic
(adh 1)	0	77	5	10 to 12	2	[12]
Maize 9S knob	70	30	0	0	0	[9]

^*Does not include simple sequence repeats. ^†Did not distinguish between predicted genes and predicted pseudogenes. ^‡Within functionally defined centromeric region, but not including central (most tandem repeat rich) region of the centromeres, which have not yet been sequenced.