Analysis of immunoglobulin organization and complexity in mink (Neovison vison)

Mink are susceptible to viruses such as SARS-CoV-2, H1N1 and H9N2, so they are considered a potential animal model for studying human viral infections. Therefore, it is important to study the immune system of mink. Immunoglobulin (Ig) is an important component of humoral immunity and plays an important role in the body's immune defense. In this study, we described the gene loci structure of mink Ig germline by genome comparison, and analysed the mechanism of expression diversity of mink antibody library by 5′RACE and next-generation sequencing (NGS). The results were as follows: the IgH, Igκ and Igλ loci of mink were located on chromosome 13, chromosome 8 and chromosome 3, respectively, and they had 25, 36 and 7 V genes, 3, 5 and 7 J genes and 10 DH genes, respectively. Mink Ig heavy chain preferred the IGHV1, IGHD2 and IGHJ4 subgroups, κ chain mainly use the IGKV1, IGKJ1 and IGHL4 subgroups, and λ chain mainly use the IGLV3 and IGLJ3 subgroups. Linkage diversity analysis revealed that N nucleotide insertion was the main factor affecting the linkage diversity of mink Igs. On the mutation types of mink Ig Somatic Hypermutation (SHM), the high mutation types of heavy chain were mainly G > A, C > T, T > C, A > G, C > A, G > T, A > C, and T > G; the high mutation types of κ chain were G > A and T > C; and the high mutation types of λ chain were G > A and A > G. The objective of this study was to analyse the loci structure and expression diversity of Ig in mink. The results contribute to our comprehension of Ig expression patterns in mink and were valuable for advancing knowledge in mink immunogenetics, exploring the evolution of adaptive immune systems across different species, and conducting comparative genomics research.