Presented here is a genome sequence of an individual human. It was produced from ∼32 million random DNA fragments, sequenced by Sanger dideoxy technology and assembled into 4,528 scaffolds, comprising 2,810 million bases (Mb) of contiguous sequence with approximately 7.5-fold coverage for any given region. We developed a modified version of the Celera assembler to facilitate the identification and comparison of alternate alleles within this individual diploid genome. Comparison of this genome and the National Center for Biotechnology Information human reference assembly revealed more than 4.1 million DNA variants, encompassing 12.3 Mb. These variants (of which 1,288,319 were novel) included 3,213,401 single nucleotide polymorphisms (SNPs), 53,823 block substitutions (2–206 bp), 292,102 heterozygous insertion/deletion events (indels)(1–571 bp), 559,473 homozygous indels (1–82,711 bp), 90 inversions, as well as numerous segmental duplications and copy number variation regions. Non-SNP DNA variation accounts for 22% of all events identified in the donor, however they involve 74% of all variant bases. This suggests an important role for non-SNP genetic alterations in defining the diploid genome structure. Moreover, 44% of genes were heterozygous for one or more variants. Using a novel haplotype assembly strategy, we were able to span 1.5 Gb of genome sequence in segments >200 kb, providing further precision to the diploid nature of the genome. These data depict a definitive molecular portrait of a diploid human genome that provides a starting point for future genome comparisons and enables an era of individualized genomic information.

One of the main goals in genome sequencing projects is to determine a haploid consensus sequence even when clone libraries are constructed from homologous chromosomes. However, it has been noticed that haplotypes can be inferred from genome assemblies by investigating phase conservation in sequenced reads. In this study, we seek to infer haplotypes, a diploid consensus sequence, from the genome assembly of an organism, Ciona intestinalis. The Ciona intestinalis genome is an ideal resource from which haplotypes can be inferred because of the high polymorphism rate (1.2%). The haplotype estimation scheme consists of polymorphism detection and phase estimation. The core step of our method is a Gibbs sampling procedure. The mate-pair information from two-end sequenced clone inserts is exploited to provide long-range continuity. We estimate the polymorphism rate of Ciona intestinalis to be 1.2% and 1.5%, according to two different polymorphism counting schemes. The distribution of heterozygosity number is well fit by a compound Poisson distribution. The N50 length of haplotype segments is 37.9 kb in our assembly, while the N50 scaffold length of the Ciona intestinalis assembly is 190 kb. We also infer diploid gene sequences from haplotype segments. According to our reconstruction, 85.4% of predicted gene sequences are continuously covered by single haplotype segments. Our results indicate 97% accuracy in haplotype estimation, based on a simulated data set. We conduct a comparative analysis with Ciona savignyi, and discover interesting patterns of conserved DNA elements in chordates. \copyright2007 by Cold Spring Harbor Laboratory Press.