Animal Molecular Breeding 2024, Vol.14, No.1, 82-85 http://animalscipublisher.com/index.php/amb 82 Scientific Commentary Open Access Genome Duplication and Gene Loss in Eels: Unraveling the Mysteries of Vertebrate Genome Dynamics JimMason Animal Molecular Breeding, Animalsci Publisher, Richmond, BC, V7A4Z5, Canada Corresponding author email: jim.mason@sophiapublisher.com Animal Molecular Breeding, 2024, Vol.14, No.1 doi: 10.5376/amb.2024.14.0010 Received: 24 Jan., 2024 Accepted: 15 Feb., 2024 Published: 24 Feb., 2024 Copyright © 2024 Mason, This is an open access article published under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Preferred citation for this article: Mason J., 2024, Genome duplication and gene loss in eels: unraveling the mysteries of vertebrate genome dynamics, Animal Molecular Breeding, 14(1): 82-85 (doi: 10.5376/amb.2024.14.0010) The paper "The hagfish genome and the evolution of vertebrates" authored by Ferdinand Marlétaz, Jeramiah J. Smith, Daniel S. Rokhsar, and others was published in Nature on January 23, 2024. The authors are affiliated with the Department of Genetics at University College London, the Department of Molecular and Cell Biology at the University of California, Berkeley, and the University of Tokyo, among others. In this study, the research team explored the genome of the jawless vertebrate, the hagfish, revealing the complex history of early vertebrate evolution and the functional role of whole genome duplication. By analyzing the chromosome-level genome sequence of the brown hagfish (Eptatretus atami), the study presents an overview of vertebrate genome evolution, including autotetraploidization that occurred in the early Cambrian period followed by subsequent whole-genome polyploidization events. Additionally, the study discovered gene-programmed deletion phenomena occurring during the early developmental stages of hagfish. These findings provide a framework for further research into the evolution of jawless and jawed vertebrates. 1 Interpretation of Experimental Data The study utilized high-resolution genome sequencing and phylogenetic analysis to reveal the phylogenetic relationships and genomic architectures of eels, lampreys, and jawed vertebrates. The results show significant collinearity between eel chromosomes and lamprey chromosomes, indicating that eel chromosomes are generally formed by the fusion of multiple lamprey chromosomes. Integrated analysis of gene trees and species trees supports that the vertebrate ancestor underwent one round of whole-genome duplication (1RV), followed by independent polyploidization events in jawed vertebrates and jawless fish (2RJV and 2RCY, respectively). Additionally, the eel genome exhibits significant gene loss, particularly genes related to eye and skeletal development, which explains the simplification of its body structure. The study also found that eels undergo gene-programmed deletion during early developmental stages, with these genes exhibiting different expression patterns in germ cells and somatic cells, revealing their critical roles in eel reproduction and development. Figure 1 displays the phylogenetic relationships and genomic collinearity architectures of eels, lampreys, and jawed vertebrates. Figure 1a shows a photograph of a brown eel. Figure 1b, based on a phylogenetic tree of 176 selected genes, displays the evolutionary relationships among chordates including jawless and jawed vertebrates. Figure 1c presents karyotype diagrams of chromosomes from eels, lampreys, and sturgeons, revealing their relationships with the ancestral chordate chromosome groups (CLGs A1, A2, and B-Q). Figure 1d, through collinearity analysis, shows that eel chromosomes are generally the result of multiple lamprey chromosomes fusing together, providing significant insights into the genomic structures of eels and lampreys.
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