At 14:00 on November 22, 2020, in Boston, USA, team BNU-China won the Gold medal in International Genetically Engineered Machine Competition (iGEM). Team BNU-China consists of 31 undergraduates from multiple colleges including College of Life Sciences, Liyun School, College of Artificial Intelligence, College of Mathematical Sciences, College of Art and Media. Students from the College of Life Science Chen Yiling acted as the team leader, Yu Yiying and Yan Ran acted as deputy team leaders; many professors and experts from the College of Life Sciences, including Zhu Xudong, Yang Dong, Hao Xiaoran, Chen Jinbo, Li Sen, Xiang Benqiong, etc. acted as instructors. This year team BNU-China overcame the huge difficulties caused by the COVID-19 and again won the gold medal. In the seven years since BNU-China started participating in iGEM in 2014, BNU-China has won four gold medals, two silvers, and one bronze.

The iGEM competition is an international top academic competition in the field of synthetic biology. It takes synthetic biology as the core and integrates life sciences, mathematics, engineering, information science, art design and other disciplines. Famous journals including Nature, Science, Scientific American, Economists as well as well-known media like BBC pay extensive attention to iGEM every year.

In 2020, BNU-China's Project Automatic Barcode Creator (ABC) uses this year's Nobel Prize-winning gene editing CRISPR/Cas9 system to establish a new DNA barcode technology for lineage tracking of individual cells in a population. CRISPR/Cas9 will introduce random mutations into the DNA barcode. Cells obtain specific barcodes during the process of growth and differentiation. Through sequence analysis, individual cells can be distinguished and cell lineage trees can be traced and drawn. The BNU-China design plan is as follows:

1. Use CLB2 promoter and degradation tag to control the action time of Cas9, so that Cas9 is coupled to cell division and automatically label each cell.

2. In order to increase the diversity of barcodes, homing guide RNA (hgRNA) that can be cut repeatedly is used instead of single guide RNA (sgRNA).

3. Considering the practical application, BNU-China combined this technology with single-cell transcriptome sequencing through dual promoters to make it possible to obtain lineage information from transcriptome information.

The ABC system established by BNU-China can help researchers to better perform cell linage. It can be used in many fields such as tumorigenesis, stem cell therapy, organ transplantation, embryo development, and screening of microbial mutant strains.

At last, the BNU-China team completed the literature research, program design, vector construction, gene expression, mathematical modeling and functional verification under heavy time pressure. After eight months’ endeavor, BNU-China clearly and perfectly showed the innovative work results through web pages, posters, promotion video and presentation video, which won unanimous praise from the contest judges, and finally contributed to this year's gold medal for BNU-China.