Table 2.

The most common 30 bp repeats with a narrow range of periodicity in different archaeal genomes. Repeats that recur more than 20 times in tandem are considered high-order repeats. The proportion of the sense strand of the genome represented by these repeats (percent of genome), the absolute number (copy number) and the mean ± SD spacer length between consecutive repeats, excluding outliers (periodicity; bp), are given. Where repeat sequences occur in two locations within the genome, mean periodicity of both locations are given. Underlined fragments depict common repetitive elements within each organism.

Organism	Repeat sequence	Percent of genome	Copy number	Periodicity
Archaeoglobus fulgidus	GTAAGAAAGGGAGGCTCCTGAAAATGGAGA	0.0018	41	46 ± 2
	TAAGAAAGGGAGGCTCCTGAAAATGGAGAT	0.0019	42	46 ± 2
	AAGAAAGGGAGGCTCCTGAAAATGGAGATT	0.0019	42	46 ± 2
	AGAAAGGGAGGCTCCTGAAAATGGAGATTG	0.0019	42	46 ± 2
	GAAAGGGAGGCTCCTGAAAATGGAGATTGA	0.0019	42	46 ± 2
	AAAGGGAGGCTCCTGAAAATGGAGATTGAA	0.0019	42	46 ± 2
	AAGGGAGGCTCCTGAAAATGGAGATTGAAA	0.0019	42	46 ± 2
	GGGAGGCTCCTGAAAATGGAGATTGAAAG	0.0019	42	47 ± 3
	AGTTGAAATCAGACCAAAATGGGATTGAAA	0.0011	23	39 ± 2
	GTTGAAATCAGACCAAAATGGGATTGAAAG	0.0028	60	39 ± 3
	CTTTCAATCCCATTTTGGTCTGATTTCAAC	0.0022	47	39 ± 3
Aeropyrum pernix	GTCCCGGGTTCAAATCCCGGCGGGCCCGCC	0.0004	7	NA
	TCCCGGGTTCAAATCCCGGCGGGCCCGCCA	0.0004	7	NA
Methanococcus jannaschii	AATTAAAATCAGACCGTTTCGGAATGGAAA	0.0017	29	40 ± 3
	ATTAAAATCAGACCGTTTCGGAATGGAAAT	0.0027	45	39 ± 3
	GTTAAAATCAGACCTCTTGGAGGATGGAAA	0.0020	33	42 ± 3
Methanothermobacter	ATTTCAATCCCATTTTGGTCTGATTTTAAC	0.0071	124	37 ± 3
thermoautotrophicus	GTTAAAATCAGACCAAAATGGGATTGAAAT	0.0024	60	37 ± 3
	AATTTCAATCCCATTTTGGTCTGATTTTAA	0.0022	39	38/105
	TATTTCAATCCCATTTTGGTCTGATTTTAA	0.0021	37	38/103
	TTTCAATCCCATTTTGGTCTGATTTTAACT	0.0021	36	36/104
	TTTCAATCCCATTTTGGTCTGATTTTAACC	0.0020	35	36/104
	TTTCAATCCCATTTTGGTCTGATTTTAACA	0.0018	31	36/105
	GATTTCAATCCCATTTTGGTCTGATTTTAA	0.0015	27	36/105
Pyrococcus abyssi	CTTTCAATTCTATTTTAGTCTTATTGGAAC	0.0012	21	38 ± 3
	GTTCCAATAAGACTAAAATAGAATTGAAAG	0.0015	26	38 ± 3
	TGTTCCAATAAGACTAAAATAGAATTGAAA	0.0007	12	39 ± 3
Pyrococcus horikoshii	TCTTTCCACACTATTTAGTTCTACGGAAAC	0.0018	32	42 ± 2
	CTTTCCACACTATTTAGTTCTACGGAAACA	0.0015	26	43 ± 3