On November 1st, Professor Frederick W. Alt, a distinguished member of the American Academy of Sciences, delivered an engaging lecture at the Shenzhen Bay Laboratory, following an invitation from Professor Chengming Zhu of the Scientific Research Center at the 7th Affiliated Hospital of Sun Yat-sen University. Professor Alt holds the position of Charles Janeway Professor of Pediatrics and Genetics at Harvard University and serves as a senior principal investigator at the Howard Hughes Medical Institute. The lecture, hosted by Professor Shen Xuetong from Shenzhen Bay Laboratory, attracted numerous principal investigators and students from both Shenzhen Bay Laboratory and Sun Yat-sen University. In his presentation titled "The Fundamental Roles of Chromatin Loop Extrusion in Antibody Diversification," Professor Alt discussed his research team's findings on the critical roles of cohesin-mediated loop extrusion in immunoglobulin heavy chain locus (Igh) V(D)J recombination. He also elucidated the molecular basis for the differences between the light chain Igk and Igh V(D)J joining mechanisms. Currently, his team is investigating the mechanism of "secondary" Igk recombination, a process that significantly contributes to the diversification of Igk repertoires and is closely associated with Igk "receptor editing" to establish central immune tolerance. Following his insightful talk, the audience engaged in a lively discussion, posing numerous intriguing questions to Professor Alt.