Fig. 1

Schematic diagram of the TRB locus and V-D-J rearrangement; schematic diagram of the object, sample and method; and statistical analysis of the TCR V-D-J rearrangement frequency in humans and mice. (A) Schematic diagram of the TRB locus and V-D-J rearrangement. According to the “12/23 rule” and the “D-J rearrangement preceding the V-(D-J) rearrangement”, the TRBD2 gene cannot directly undergo inversional recombination or deletional/loop-out recombination with the TRBJ1gene. (B) Schematic diagram of the object, sample and method. We utilized a total of 42 samples from five mammalian species, obtained TRB CDR repertoires through HTS and scTCR-seq technologies, and employed tools to perform alignment on the TRB CDR repertoires to identify V, D, and J subfamily gene sequences. (C) Statistical analysis of the TCR V-D-J rearrangement frequency in humans and mice. We analyzed the usage frequency of VDJ genes in the TRB CDR repertoires of human and mouse samples, presenting the data using dot plots and heatmaps. Statistical analyses were conducted between D1 and D2, between D1-J1 and D1-J2, between D2-J1 and D2-J2, and between V30(V31)-D2J1 and VX-D2J1. Note: (1) D1 is the complete sequence (complete Vx-D1-Jx) of all D1 genes involved in the rearrangement of each sample; D2 is the complete sequence (complete Vx-D2-Jx) of all D2 genes involved in the rearrangement of each sample; D1 + D2 = 100%; D1-J1 denotes total Vx-D1-J1; D1-J2 denotes total Vx-D1-J2; D1-J1 + D1-J2 = 100%; D2-J1 denotes total Vx-D2-J1; D2-J2 denotes total Vx-D2-J2; D2-J1 + D2-J2 = 100%; V30(or V31)-D2-J1 + Vx-D2-J1 = 100%. (2) The heatmap is a visual comparison of the objective existence and relatively low frequency of D2-J1 rearrangement usage. (3) Visualization of D-J (V-D-J) recombination and usage of D genes. We used a dot plot for sample groups with n ≥ 3 and performed statistical analysis using Mann Whitney U test. All statistically significant differences are indicated as *P value < 0.05 and **P value < 0.01