On June 14, 2023, China Central Television News Channel reported that 26 research institutions, including Fudan University and Xi'an Jiaotong University, jointly conducted a study to draw a pan genomic reference map of the Chinese population based on 36 ethnic groups in China. The related results were published in the international authoritative journal Nature on June 14, Beijing time. This is also the first major achievement achieved by Chinese scientists in independently conducting panoramic genomics research on their own population.

 

Compared to genomes from a single individual, the pan genome reference map has a wider range and includes the complete set of all genomes in a species or population. The sequence released by the China Pan Genome Alliance (CPC) this time combined 58 samples from 36 ethnic minorities in China, confirming the necessity of high-quality population specific genomes in genetic and medical applications, helping us to have a more comprehensive understanding of genomic variations in East Asian populations, especially in the Chinese population.

 

The article used the latest genome sequencing technology to conduct in-depth sequencing on 58 samples representing 36 ethnic groups in China. Combined with the latest haplotype genome assembly method, 116 high-quality haplotype genomes were obtained, and a high-quality Chinese population reference pan genome was constructed in the form of a graph genome.

 

 

 

The sequencing technology in the article simultaneously utilizes NGS high-throughput sequencing, PacBio HiFi sequencing, and Oxford Nanopore length long sequencing. By combining the latest haplotype genome assembly method, 116 high-quality haplotype genomes were obtained, and a high-quality reference pan genome for the Chinese population was constructed in the form of a graph genome.

 

The map contains approximately 3.01 Gb of sequence information, with approximately 190 million new base pairs added to the existing human reference genome, including approximately 5.9 million small variations (single nucleotide polymorphism and small insertion/deletion variations) and approximately 34000 structural variations (SV), involving at least 1367 protein coding gene replication events. Among them, about 5 million new base pairs exist in over 95% of haplotypes and are considered as the core sequence of the Chinese genome, which may be related to the relatively stable biological functions or phenotypic characteristics unique to the Chinese population.

 

 

The PacBio HiFi sequencing technology used in the article can achieve both long read length and high accuracy DNA sequencing simultaneously. To ensure the yield and quality of HiFi sequencing, it is necessary to control the DNA library size within the range of 15-25kb. Therefore, high-precision fragment screening is one of the key steps in PacBio Hifi sequencing. The Blue Pippin, a fully automated DNA fragment recovery instrument based on pulsed field electrophoresis provided by Sage Science, can meet the above requirements and has become one of the gold standards and essential tools for constructing HiFi libraries.

 

 

Another application is Oxford Nanopore sequencing technology, which has the advantage of ultra long read length and effectively solves the problem of difficult splicing of human, animal and plant genomes, crossing the difficult sequencing regions on chromosomes. It has broad applications in research fields such as large genome splicing, large fragment structural variation analysis, and mutation phase analysis. To better leverage the advantages of Nanopore sequencing, it is required to preserve long DNA fragments as much as possible during the library construction process, flexibly and efficiently remove small DNA fragments, in order to obtain high-quality Nanopore sequencing data. PippinHT and other series of products are currently widely used in Nanopore customers.