Twin peaks: the draft human genome sequence

Table 1 A comparison of three draft genome sequence assemblies

Assembly	Celera	HGP-nr	UCSC
Reference	[2]	[11]	[13]
Length (gigabases)	2.9	2.9	3.3
Sequenced bases (gigabases)	2.66	2.84	2.69
Number of gaps	21,684	181,079	145,514
Number of contigs	54,061	6,094	4,884
N50 length^* (megabases)	0.8	2.8	2.3
HGP data version used	1/09/00	?/12/00	07/10/00

^*N50 length is a measure of the contig length containing the 'typical' nucleotide. Specifically, it is the maximal length L such that 50% of all nucleotides lie in contigs of size at least L. See text for further details of the three assemblies.

ISSN: 1474-760X