NHGI ((National Human Genome Research Institute)와 University of California, Santa Cruz의 연구자들이 이끄는 국제연구팀은  이제껏 못 풀었던 성염색체 시퀀스의 넓은 범위를 밝혀냈습니다. Bionano genomics optical mapping, PacBio HiFi log read등 다양한 플랫폼을 적용하여 X 염색체의 완벽하고 갭이 없는 어셈블리를 조립하고 분석하기 시작했습니다.
PacBio Hifi Long read를 적용하여 다른 플랫폼에서 생성된 에러를 바로 잡아 완성도를 높였습니다.  

Abstract : After two decades of improvements, the current human reference genome (GRCh38) is the most accurate and complete vertebrate genome ever produced. However, no one chromosome has been finished end to end, and hundreds of unresolved gaps persist. Here we present a de novo human genome assembly that surpasses the continuity of GRCh38, along with the first gapless, telomere-to-telomere assembly of a human chromosome. This was enabled by high-coverage, ultra-long-read nanopore sequencing of the complete hydatidiform mole CHM13 genome, combined with complementary technologies for quality improvement and validation. Focusing our efforts on the human X chromosome, we reconstructed the ~3.1 megabase centromeric satellite DNA array and closed all 29 remaining gaps in the current

reference, including new sequence from the human pseudoautosomal regions and cancer-testis ampliconic gene families (CT-X and GAGE). These novel sequences will be integrated into future human reference genome releases. Additionally, a complete chromosome X, combined with the ultra-long nanopore data, allowed us to map methylation patterns across complex tandem repeats and satellite arrays for the first time. Our results demonstrate that finishing the entire human genome is now within reach and the data presented here will enable ongoing efforts to complete the remaining human chromosomes.