{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,2,23]],"date-time":"2026-02-23T06:10:58Z","timestamp":1771827058121,"version":"3.50.1"},"reference-count":23,"publisher":"Frontiers Media SA","license":[{"start":{"date-parts":[[2026,2,23]],"date-time":"2026-02-23T00:00:00Z","timestamp":1771804800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":["frontiersin.org"],"crossmark-restriction":true},"short-container-title":["Front. Immunol."],"abstract":"<jats:sec>\n                    <jats:title>Background<\/jats:title>\n                    <jats:p>\n                      We previously reported the genomic characterization of immunoglobulin loci in\n                      <jats:italic>Ambystoma mexicanum<\/jats:italic>\n                      of the laboratory d\/d white strain, where the IGH locus gene orientation was incompatible with VDJ recombination, suggesting scaffold orientation errors. A novel 29.1 Gbp\n                      <jats:italic>A. mexicanum<\/jats:italic>\n                      genome derived from an F1 cross between\n                      <jats:italic>A. mexicanum<\/jats:italic>\n                      and\n                      <jats:italic>A. tigrinum<\/jats:italic>\n                      (UKY_AmexF1_1) has recently been released, containing only 220 unmapped scaffolds. Here, we present an updated description of the immunoglobulin loci based on this improved genome assembly.\n                    <\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Methods<\/jats:title>\n                    <jats:p>Using our previously annotated AmbMex60DD sequences, we performed an alignment-based annotation followed by manual curation on the UKY_AmexF1_1 assembly. Gene models were further refined using RNA-Seq datasets from axolotl spleen, liver, lung, heart, and gill tissues.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Results<\/jats:title>\n                    <jats:p>The IGH locus was mapped at 350\u2013364 Mbp on chromosome 13q. Synteny is preserved between both genome versions, but in UKY_AmexF1_1, all IGH genes share the same transcriptional orientation. A major difference was observed in the lambda locus, which in the UKY_Amex_F1_1 genome contains 13 IGLC\u2013IGLJ clusters comprising 60 IGLJ genes, compared with only three clusters in the AmbMex60DD genome. No kappa locus was detected in either assembly.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Conclusion<\/jats:title>\n                    <jats:p>\n                      This study confirms our previous findings and provides an example of intraspecies structural variation in adaptive immune receptor loci. It underscores the importance of well-assembled genomes and establishes the current\n                      <jats:italic>A. mexicanum<\/jats:italic>\n                      reference as a valuable resource for investigating immune evolution and function in axolotls and other vertebrates.\n                    <\/jats:p>\n                  <\/jats:sec>","DOI":"10.3389\/fimmu.2026.1736245","type":"journal-article","created":{"date-parts":[[2026,2,23]],"date-time":"2026-02-23T05:28:02Z","timestamp":1771824482000},"update-policy":"https:\/\/doi.org\/10.3389\/crossmark-policy","source":"Crossref","is-referenced-by-count":0,"title":["An update on the characterization of immunoglobulin loci in Ambystoma mexicanum"],"prefix":"10.3389","volume":"17","author":[{"given":"Stephanie","family":"Saint Remy-Hern\u00e1ndez","sequence":"first","affiliation":[{"name":"Departamento de Parasitolog\u00eda, Posgrado en Ciencias Quimicobiol\u00f3gicas, Escuela Nacional de Ciencias Biol\u00f3gicas, Instituto 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