A short DNA sequence is becoming the key to unlocking Earth's biodiversity mysteries, providing "genetic ID cards" for species identification.
Explore the ScienceIn biological research, accurate species identification is fundamental. Traditional morphological identification requires specialized expertise and often fails with eggs, larvae, or incomplete specimens.
DNA barcoding uses a short, standardized gene sequence for rapid, accurate species identification. Like an ID card number uniquely identifies a person, this gene sequence distinguishes different species.
The sequences between individuals of the same species show high similarity, while significant differences exist between different species. By comparing these sequences, researchers can identify which species a sample belongs to, and even discover previously undescribed new species.
In DNA barcoding's early development, scientists primarily relied on Sanger sequencing. While accurate, this method could only obtain one sequence per reaction, with low efficiency and high costs1 .
Traditional Sanger sequencing cost about $10 per sample on average. Building a barcode dataset for 100 million samples would require $1 billion1 .
With the推广 of High-Throughput Sequencing (HTS) technologies, DNA barcode acquisition efficiency greatly improved1 .
Recent years have seen various innovative methods emerge, such as the HIFI-Barcode method, which combines high-throughput sequencing technology with bioinformatics analysis pipelines to achieve economical, rapid, and efficient acquisition of standard COI barcode sequences1 .
This method can obtain 96 high-quality full-length COI barcodes at once, greatly improving research efficiency1 .
By 2013, DNA barcoding functions were categorized into three types: basic functions (data storage, species identification), extended functions (constructing phylogenetic relationships, serving specific industries), and potential functions (species integration)2 .
Based on research scale, it can be divided into three levels: taxa, community, and regional levels2 .
Efficient implementation of DNA barcoding technology relies on standardized experimental procedures. Taking the HIFI-Barcode method as an example, a complete barcode acquisition experiment includes three main stages1 .
Researchers first extract DNA from each sample individually, performed on 96-well plates. After DNA extraction, PCR amplification is conducted using 96 pairs of barcode amplification primers with specific tag sequences1 .
Selection of sequencing platform based on project requirements. Common platforms include Illumina, MGISEQ, and Pacific Biosciences (Pacbio). Platform choice affects subsequent data analysis workflows1 .
After sequencing completion, specialized software packages are used for analysis, ultimately obtaining multiple high-quality full-length COI barcodes at once1 .
| Comparison Dimension | HIFI-Barcode-Hiseq/MGISEQ | HIFI-Barcode-Pacbio | HIFI-Barcode-SE400 |
|---|---|---|---|
| Sequencing Technology | PE150 | Long-read single-molecule real-time sequencing | SE400 |
| Read Length Characteristics | Short reads, requires assembly | Long reads, no assembly needed | Ultra-long reads, requires simple assembly |
| Data Analysis Complexity | High | Medium | Low |
| Main Application Scenarios | Large-scale samples, cost-sensitive | Research requiring long reads | Rapid acquisition of full-length barcodes |
As DNA barcoding technology continues to develop, its application fields are constantly expanding. From early species identification to current ecosystem research, this technology is playing an increasingly important role2 .
Primarily focused on specific taxonomic group studies. DNA barcoding is used to clarify species boundaries and discover cryptic species.
Example: Through analysis of rpoB barcodes in Lycium plants, scientists successfully distinguished Ningqi No. 1, black fruit wolfberry, northern wolfberry, and other varieties4 , solving identification challenges for morphologically similar varieties.
Biological communities composed of nature reserves and large fixed plots. DNA barcoding helps scientists understand interspecies relationships in ecosystems.
Example: By analyzing DNA barcodes in fish stomach contents, researchers can reconstruct food webs and understand predator diet composition.
Biodiversity hotspot areas. DNA barcoding provides powerful tools for research in biodiversity hotspot regions.
Example: The International Barcode of Life organization has launched ten major research projects covering multiple fields from systematics and taxonomy to biodiversity conservation2 .
| Biological Group | Standard Barcode Region | Characteristics | Application Example |
|---|---|---|---|
| Animals | Mitochondrial COI gene | Moderate mutation rate, strong universality | Insect, fish, bird identification |
| Plants | Multiple chloroplast gene fragments | Single region discrimination insufficient, requires combination | Lycium rpoB barcode identification4 |
| Fungi | ITS sequences | Ribosomal gene spacer region, high variation | Fungal diversity research |
DNA barcoding research relies on a series of specialized reagents, software, and equipment. Below are the core components needed for related experiments:
DNA barcoding technology has experienced rapid development over the past decade, but its potential remains untapped. In the future, this technology may continue evolving in multiple directions2 .
An important direction for DNA barcoding technology development. As data volumes continuously increase, integrating DNA barcode data with other data types (such as ecological data, behavioral data, etc.) will become key to advancing the discipline2 .
Another important focus for future work. Although standardized processes exist, methodological and analytical differences still persist between different laboratories. Promoting technical standardization will help improve comparability and reproducibility of research results1 .
Equally important. Although the Barcode of Life Database (BOLD) already contains approximately 8 million barcode sequences covering about 300,000 species (as of February 2020), this is just the tip of the iceberg for global biodiversity1 .
As sequencing technology continues advancing and costs keep declining, DNA barcoding is expected to achieve more comprehensive and rapid recording and identification of Earth's organisms in the future.
Perhaps soon, everyone will be able to read biological DNA barcodes through portable devices, as simple as scanning product barcodes in supermarkets. Then, human understanding of the natural world will enter a completely new era.