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Takeuchi T, Suzuki Y, Watabe S, Nagai K, Masaoka T, Fujie M, Kawamitsu M, Satoh N, Myers EW. A high-quality, haplotype-phased genome reconstruction reveals unexpected haplotype diversity in a pearl oyster. DNA Res 2022; 29:dsac035. [PMID: 36351462 PMCID: PMC9646362 DOI: 10.1093/dnares/dsac035] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2022] [Revised: 08/18/2022] [Accepted: 09/12/2022] [Indexed: 07/30/2023] Open
Abstract
Homologous chromosomes in the diploid genome are thought to contain equivalent genetic information, but this common concept has not been fully verified in animal genomes with high heterozygosity. Here we report a near-complete, haplotype-phased, genome assembly of the pearl oyster, Pinctada fucata, using hi-fidelity (HiFi) long reads and chromosome conformation capture data. This assembly includes 14 pairs of long scaffolds (>38 Mb) corresponding to chromosomes (2n = 28). The accuracy of the assembly, as measured by an analysis of k-mers, is estimated to be 99.99997%. Moreover, the haplotypes contain 95.2% and 95.9%, respectively, complete and single-copy BUSCO genes, demonstrating the high quality of the assembly. Transposons comprise 53.3% of the assembly and are a major contributor to structural variations. Despite overall collinearity between haplotypes, one of the chromosomal scaffolds contains megabase-scale non-syntenic regions, which necessarily have never been detected and resolved in conventional haplotype-merged assemblies. These regions encode expanded gene families of NACHT, DZIP3/hRUL138-like HEPN, and immunoglobulin domains, multiplying the immunity gene repertoire, which we hypothesize is important for the innate immune capability of pearl oysters. The pearl oyster genome provides insight into remarkable haplotype diversity in animals.
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Affiliation(s)
| | - Yoshihiko Suzuki
- Present address: Department of Computational Biology and Medical Sciences, The University of Tokyo, Kashiwa, Chiba, Japan
| | - Shugo Watabe
- Kitasato University School of Marine Biosciences, Sagamihara, Kanagawa, Japan
| | - Kiyohito Nagai
- Pearl Research Institute, K. MIKIMOTO & CO., LTD, Shima, Mie, Japan
| | - Tetsuji Masaoka
- Aquatic Breeding Division, Aquaculture Research Department, Fisheries Technology Institute, Japan Fisheries Research and Education Agency, Tamaki, Mie, Japan
| | - Manabu Fujie
- DNA Sequencing Section, Okinawa Institute of Science and Technology Graduate University, Onna, Okinawa, Japan
| | - Mayumi Kawamitsu
- DNA Sequencing Section, Okinawa Institute of Science and Technology Graduate University, Onna, Okinawa, Japan
| | - Noriyuki Satoh
- Marine Genomics Unit, Okinawa Institute of Science and Technology Graduate University, Onna, Okinawa, Japan
| | - Eugene W Myers
- Algorithms for Eco and Evo Genomics Unit, Okinawa Institute of Science and Technology Graduate University, Onna, Okinawa, Japan
- Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany
- Center for Systems Biology Dresden, Dresden, Germany
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