De novo assembly and phasing of a Korean human genome.

Advances in genome assembly and phasing provide an opportunity to investigate the diploid architecture of the human genome and reveal the full range of structural variation across population groups. Here we report the de novo assembly and haplotype phasing of the Korean individual AK1 (ref. 1) using single-molecule real-time sequencing, next-generation mapping, microfluidics-based linked reads, and bacterial artificial chromosome (BAC) sequencing approaches. Single-molecule sequencing coupled with next-generation mapping generated a highly contiguous assembly, with a contig N50 size of 17.9 Mb and a scaffold N50 size of 44.8 Mb, resolving 8 chromosomal arms into single scaffolds. The de novo assembly, along with local assemblies and spanning long reads, closes 105 and extends into 72 out of 190 euchromatic gaps in the reference genome, adding 1.03 Mb of previously intractable sequence. High concordance between the assembly and paired-end sequences from 62,758 BAC clones provides strong support for the robustness of the assembly. We identify 18,210 structural variants by direct comparison of the assembly with the human reference, identifying thousands of breakpoints that, to our knowledge, have not been reported before. Many of the insertions are reflected in the transcriptome and are shared across the Asian population. We performed haplotype phasing of the assembly with short reads, long reads and linked reads from whole-genome sequencing and with short reads from 31,719 BAC clones, thereby achieving phased blocks with an N50 size of 11.6 Mb. Haplotigs assembled from single-molecule real-time reads assigned to haplotypes on phased blocks covered 89% of genes. The haplotigs accurately characterized the hypervariable major histocompatability complex region as well as demonstrating allele configuration in clinically relevant genes such as CYP2D6. This work presents the most contiguous diploid human genome assembly so far, with extensive investigation of unreported and Asian-specific structural variants, and high-quality haplotyping of clinically relevant alleles for precision medicine.

Comparison of vegetable oils on the uptake of lutein and zeaxanthin by ARPE-19 cells.

AIM: To compare the effect of vegetable oils on the uptake of lutein and zeaxanthin by adult retinal pigment epithelial (ARPE)-19 cells in vitro. METHODS: ARPE-19 cells were cultured in Dulbecco's Modified Eagle Medium-F-12 supplemented with 10% foetal bovine serum and 1% penicillin-streptomycin in a humidified 5% CO2 incubator maintained at 37°C. Cells were treated with 247 µmol/L lutein, 49 µmol/L zeaxanthin and 1% (v/v) of either coconut oil, corn oil, peanut oil, olive oil, sunflower oil, soybean oil, castor oil, or linseed oil for 48h. Lutein and zeaxanthin concentration in the cells were quantified by high performance liquid chromatography. RESULTS: Among the oils tested, the highest lutein and zeaxanthin uptake was observed with coconut oil while the lowest was observed with linseed oil. CONCLUSION: ARPE-19 uptake of lutein and zeaxanthin are found to be dependent on the type of oils.

Genome assembly of the popular Korean soybean cultivar Hwangkeum.

Massive resequencing efforts have been undertaken to catalog allelic variants in major crop species including soybean, but the scope of the information for genetic variation often depends on short sequence reads mapped to the extant reference genome. Additional de novo assembled genome sequences provide a unique opportunity to explore a dispensable genome fraction in the pan-genome of a species. Here, we report the de novo assembly and annotation of Hwangkeum, a popular soybean cultivar in Korea. The assembly was constructed using PromethION nanopore sequencing data and two genetic maps and was then error-corrected using Illumina short-reads and PacBio SMRT reads. The 933.12 Mb assembly was annotated as containing 79,870 transcripts for 58,550 genes using RNA-Seq data and the public soybean annotation set. Comparison of the Hwangkeum assembly with the Williams 82 soybean reference genome sequence (Wm82.a2.v1) revealed 1.8 million single-nucleotide polymorphisms, 0.5 million indels, and 25 thousand putative structural variants. However, there was no natural megabase-scale chromosomal rearrangement. Incidentally, by adding two novel subfamilies, we found that soybean contains four clearly separated subfamilies of centromeric satellite repeats. Analyses of satellite repeats and gene content suggested that the Hwangkeum assembly is a high-quality assembly. This was further supported by comparison of the marker arrangement of anthocyanin biosynthesis genes and of gene arrangement at the Rsv3 locus. Therefore, the results indicate that the de novo assembly of Hwangkeum is a valuable additional reference genome resource for characterizing traits for the improvement of this important crop species.

Complete genome sequence of the diesel-degrading Acinetobacter sp. strain DR1.

The genus Acinetobacter is ubiquitous in soil, aquatic, and sediment environments and includes pathogenic strains, such as A. baumannii. Many Acinetobacter species isolated from various environments have biotechnological potential since they are capable of degrading a variety of pollutants. Acinetobacter sp. strain DR1 has been identified as a diesel degrader. Here we report the complete genome sequence of Acinetobacter sp. DR1 isolated from the soil of a rice paddy.

Draft Genome Sequences of Fusobacterium nucleatum ChDC F145, ChDC F174, ChDC F206, and ChDC F300, Isolated from Human Subgingival Plaques in the Republic of Korea.

Recently, five strains were isolated from human subgingival plaques and were proposed as a novel subspecies of Fusobacterium nucleatum. Here, we report the draft genome sequences of the strains, except one for which the draft sequence was already introduced.

Draft Genome Sequence of Fusobacterium nucleatum subsp. nucleatum ChDC F316, Isolated from a Human Peri-implantitis Lesion in the Republic of Korea.

Fusobacterium nucleatum is a Gram-negative anaerobe and is one of the causative agents of periodontal diseases, including peri-implantitis. Fusobacterium nucleatum subsp. nucleatum ChDC F316 (KCOM 1322) was isolated from a human peri-implantitis lesion. Here, we report the draft genome sequence of this strain.

Draft Genome Sequence of Fusobacterium nucleatum subsp. vincentii ChDC F8, Isolated from a Human Subgingival Plaque in the Republic of Korea.

Fusobacterium nucleatum is a Gram-negative, nonmotile, obligately anaerobic rod bacterium which might play an important role in the initiation and progression of periodontal diseases. F. nucleatum subsp. vincentii ChDC F8 (KCOM 1231) was isolated from a human gingivitis lesion. Here, we report the draft genome sequence of the strain.

Draft Genome Sequence of Fusobacterium nucleatum subsp. animalis ChDC F324, Isolated from a Human Subgingival Plaque in the Republic of Korea.

Five subspecies of Fusobacterium nucleatum have been classified: animalis, nucleatum, polymorphum, vincentii, and fusiforme. F. nucleatum subsp. animalis ChDC F324 (KCOM 1325) was isolated from a human subgingival plaque in the Republic of Korea. Here, we report the draft genome sequence of the strain.

Draft Genome Sequence of the Novel Peptoniphilus sp. Strain ChDC B134, Isolated from a Human Periapical Abscess Lesion.

The genus Peptoniphilus comprises butyrate-producing, nonsaccharolytic species that use peptone and amino acids as major energy sources. The novel Peptoniphilus sp. strain ChDC B134 (=KCOM 1628) was isolated from a human periapical abscess lesion. Here, we report the draft genome sequence of the strain.