The publication reports the draft genome sequence and annotation of *Brassica rapa*, a mesopolyploid crop species. The genome contains 41,174 protein-coding genes, and *B. rapa* has experienced a second genome triplication, making it a unique model for studying the consequences of polyploidy. The study reveals that gene loss varies among triplicated segments, with one copy retaining a higher proportion of genes (70%) compared to the other two (46% and 36%). The genome's rapid evolutionary rate and specific copy number amplifications of gene families contribute to the development of new morphological variants in Brassica species. The *B. rapa* genome provides a valuable resource for comparative and evolutionary analysis of Brassicaceae genomes and genetic improvement of Brassica crops. The study also highlights the importance of transposable elements and the retention of genes following polyploidy, which may influence gene function and environmental adaptability.The publication reports the draft genome sequence and annotation of *Brassica rapa*, a mesopolyploid crop species. The genome contains 41,174 protein-coding genes, and *B. rapa* has experienced a second genome triplication, making it a unique model for studying the consequences of polyploidy. The study reveals that gene loss varies among triplicated segments, with one copy retaining a higher proportion of genes (70%) compared to the other two (46% and 36%). The genome's rapid evolutionary rate and specific copy number amplifications of gene families contribute to the development of new morphological variants in Brassica species. The *B. rapa* genome provides a valuable resource for comparative and evolutionary analysis of Brassicaceae genomes and genetic improvement of Brassica crops. The study also highlights the importance of transposable elements and the retention of genes following polyploidy, which may influence gene function and environmental adaptability.