The genomic loci encoding the four immunoglobulin light chains (IgL1, IgL2, IgL3, and IgL4) in the Swanson trout genome assembly were annotated in order to provide a measurement of the potential IgL repertoire. IgL1 and IgL3 gene segments are co-localized on chromosomes 21, 18, 15, and 7 while IgL2 and IgL4 were found on chromosomes 13 and 17, respectively. In total, 48 constant (C_L), 87 variable (V_L), and 59 joining (J_L) productive genes are described. Pairwise alignment of the V_L segments revealed that they belong to nine different families, three of which (kappa IV, V, and VI) are described for the first time in this study. V_L and C_L sequences on chromosome 15 and 21 and those on chromosomes 7 and 18 clustered together in phylogenetic analysis. PCR was used to examine IgL C_L and V_L genes in 9 lines of rainbow trout. IgL4 in the Hot Creek and Golden trout lines was missing 42 nucleotides resulting in a loss of 14 amino acids. The sigma IV variable family was completely absent from the Swanson, Arlee, Hot Creek, and wild type lines and silenced in the Skamania line with the addition of 176 bp mini-satellite insert. Similarly, the Whale Rock, Arlee, and wild type lines were all found to encode two sigma II products, a functional 252 bp product and a larger 425 bp product that contained a 172 bp insert. Results from this study indicate that there are genomic differences in IgL repertoire between different lines of trout that could affect humoral immune responses post vaccination and during disease.

对 Swanson 鳟鱼基因组组装中的四个免疫球蛋白轻链（IgL1、IgL2、IgL3 和 IgL4）进行编码的基因组位点进行了注释，以测量潜在的 IgL 库。IgL1 和 IgL3 基因片段共定位在 21、18、15 和 7 号染色体上，而 IgL2 和 IgL4 分别位于 13 号和 17 号染色体上。总共描述了 48 个恒定 ( _CL )、87 个可变 ( _VL ) 和 59 个连接 (J _L ) 生产基因。V _L段的成对比对表明它们属于九个不同的家族，其中三个（kappa IV、V 和 VI）在本研究中首次被描述。V _L和 C _L15 号和 21 号染色体上的序列以及 7 号和 18 号染色体上的序列在系统发育分析中聚集在一起。PCR 用于检测 IgL C _L和 V _L9 系虹鳟鱼的基因。Hot Creek 和 Golden trout 品系中的 IgL4 缺失 42 个核苷酸，导致 14 个氨基酸缺失。sigma IV 变量家族在 Swanson、Arlee、Hot Creek 和野生型品系中完全不存在，而在 Skamania 品系中通过添加 176 bp 微型卫星插入片段而沉默。类似地，Whale Rock、Arlee 和野生型品系都被发现编码两个 sigma II 产品，一个功能性 252 bp 产品和一个包含 172 bp 插入片段的更大的 425 bp 产品。这项研究的结果表明，不同种类的鳟鱼之间的 IgL 库存在基因组差异，这可能会影响疫苗接种后和疾病期间的体液免疫反应。