Somatic hypermutation of TCR γ V genes in the sandbar shark

► This paper characterizes SHM patterns in shark TCR γ chains. ► We identify shark hotspot motifs identical to those of mammals. ► Mechanism of SHM in shark B cells and T cells are very similar. ► Point mutations in sharks and mammals are generated by similar mechanisms. ► We propose a model for the generation of tandem mutations found only in shark SHM.