Molecular characterization and complexity of the immunoglobulin repertoire in the silver-black fox (Vulpes vulpes)

Immunoglobulins, a class of globulins with antibody properties, play a crucial role in the body's defense against pathogens. In this study, we analyzed the gene loci structure of Silver-black fox using a comparative genomics approach. The mechanisms of expression diversity and its preferences were investigated through Next-generation sequencing (NGS). The results revealed 32 potentially functional VH genes, 9 Vκ genes, 17 Vλ genes, 9 DH genes, 3 JH genes, 6 Jκ genes, and 11 Jλ genes, located on different scaffolds. Subsequently, 5'RACE and PE300 bipartite sequencing were used to obtain the reads of the expressed antibody repertoire of Silver-black foxes gene rearrangement events. The analysis indicated a strong preference in the use of V genes, DH genes and J genes by Silver-black fox. The main ways of expression diversity were V(D)J recombination and somatic hypermutation (SHM). The hypermutated region of SHM was not only concentrated in the CDR region but also had higher mutation rate in the FR region. The main types of SHM were G > A, C > T, T > C, and A > G. The findings of this study could serve as a theoretical foundation for a deeper understanding of Silver-black fox immunoglobulins, which is significant for enriching knowledge in immunogenetics and providing theoretical support for future studies on vaccine design for the Silver-black fox.