Silent protection

Unveiled at this year's Two Sessions, an environmental DNA (eDNA) sequencing chip has captured attention for its ability to monitor aquatic species in the Yangtze River such as the finless porpoise, affectionately known as the "smiling angel of the Yangtze," without the need for direct contact. The chip integrates eDNA monitoring data collected from 19 sections of the Yangtze in Jiangsu Province. Over the past five years, more than 20 additional species have been recorded along this stretch, highlighting the positive impact of the 10-year fishing ban implemented across the entire river since 1 January 2021.

The eDNA technology works by analysing the genetic traces organisms leave behind in water or sediments, including cells, secretions and other organic residues, and comparing them with reference sequences to accurately identify species. Developed by the Chinese company MGI Tech and paired with a high-throughput sequencer, the chip can detect even low-quality and low-concentration DNA in complex natural environments.

In practical terms, collecting a small water sample from various points along the river is sufficient. By analysing these minute DNA traces, researchers can monitor changes in the distribution and abundance of rare species, enabling "silent" protection. For invasive species, sequencing data allows precise tracking of population expansion, early warning and improved ecological safety in waterways.

One key partner is the Hubei Provincial Ecological Monitoring Centre, which houses the first domestic DNA laboratory equipped with locally produced instruments. Commissioned in late 2023, the laboratory has conducted pilot projects along the Hubei section of the river, gradually establishing a comprehensive technical system. According to Wu Dongqing, staff member of the centre, the chip can hold 500 samples. Once placed with reagents in a high-throughput sequencer, results are automatically transmitted and analysed within 12 hours.

Traditional fish monitoring methods, which rely on capturing and visually identifying species, are time-consuming, costly and potentially disruptive to rare species. The eDNA technology eliminates the need for physical capture, fully aligning with the fishing ban policy. Using standardised experimental procedures, specialised equipment and a unified DNA database, it reduces reliance on human expertise and minimises observation errors. The results are accurate, verifiable and fully traceable.

Already deployed in provinces including Hubei, Zhejiang, Shaanxi and Guangdong, the technology is expanding to monitor plankton, microorganisms in desert soils and even the traces left by migratory birds. Small in size but vast in potential, this chip is helping to build a veritable "genetic archive" of ecosystems.