Archived data for: Balancing selection, genetic drift, and human mediated-introgression interplay to shape MHC (functional) diversity in Mediterranean brown trout

The extraordinary polymorphism of Major Histocompatibility Complex (MHC) genes is considered a paradigm of pathogen-mediated balancing selection, although empirical evidence is still scarce. Furthermore, the relative contribution of balancing selection to shape MHC population structure and diversity, compared to that of neutral forces, as well as its interaction with other evolutionary processes such as hybridization, remains largely unclear. To investigate these issues, we analysed adaptive (MHC-DAB gene) and neutral (11 microsatellite loci) variation in 156 brown trout (Salmo trutta complex) from six wild populations in central Italy exposed to introgression from domestic hatchery lineages (assessed with the LDH gene). MHC diversity and structuring correlated with those at microsatellites, indicating the substantial role of neutral forces. However, individuals carrying locally rare MHC alleles/supertypes (regardless of the zygosity status and degree of sequence dissimilarity of MHC) w...

主要组织相容性复合体（Major Histocompatibility Complex, MHC）基因的极端多态性被视为病原体介导平衡选择的经典范式，尽管相关实证证据仍较为匮乏。此外，相较于中性进化力量，平衡选择对塑造MHC种群结构与遗传多样性的相对贡献，及其与杂交等其他进化过程的互作机制，目前仍在很大程度上尚不明确。为探究上述问题，本研究对意大利中部6个野生种群的156条褐鳟（Salmo trutta complex）开展了遗传变异分析，分别检测了适应性基因（MHC-DAB基因）与中性遗传标记（11个微卫星位点）的变异情况。这些种群均受到了养殖孵化场谱系的基因渐渗影响，我们通过乳酸脱氢酶（LDH）基因对该渐渗程度进行了评估。研究结果显示，MHC的遗传多样性与种群结构与微卫星标记的相关结果存在显著关联，表明中性进化力量发挥了重要作用。然而，携带本地稀有MHC等位基因/MHC超型的个体（无论其MHC的接合状态以及序列差异程度如何）……