Institute of Marine Ecology and Conservation, National Sun Yat-Sen University, Kaohsiung, Taiwan.
Department of Aquaculture, National Taiwan Ocean University, Keelung, Taiwan.
Sci Rep. 2023 Feb 20;13(1):2963. doi: 10.1038/s41598-023-29218-3.
Directional asymmetry indicates a unidirectional deviation from perfect bilateral symmetry, which was rarely examined in the inner organs of the teleost (Teleostei) compared to external traits. This study examines the directional asymmetry in the gonad length of 20 species of moray eels (Muraenidae) and two outgroup species with 2959 individuals. We tested three hypotheses: (1) moray eel species did not exhibit directional asymmetry in the gonad length; (2) the directional asymmetry pattern was the same for all selected species; (3) the directional asymmetry was not related to the major habitat types, depth and size classes, and taxonomic closeness of the species. Moray eels were generally "right-gonadal", the right gonad length being constantly and significantly longer than the left one in all studied Muraenidae species. The degree of asymmetry varied among species and was not significantly related to taxonomic closeness. The habitat types, depth, and size classes had intermingled effects on observed asymmetry without a clear correspondence. The directional asymmetry in the gonad length is a unique and widely occurring phenomenon in the Family Muraenidae, which was likely a by-product in the evolutionary history without significant disadvantage in survival.
方向性不对称表示从完美的双侧对称存在单向偏差，与外部特征相比，这种偏差在硬骨鱼（硬骨鱼纲）的内部器官中很少被研究。本研究检查了 20 种海鳝（海鳝科）和 2 个外群物种的 2959 个个体的性腺长度的方向性不对称。我们检验了三个假设：（1）海鳝物种的性腺长度没有表现出方向性不对称；（2）所有选定物种的方向性不对称模式相同；（3）方向性不对称与主要的栖息地类型、深度和大小类以及物种的分类亲缘关系无关。海鳝通常是“右侧性腺”，右侧性腺长度始终比左侧性腺长，所有研究的海鳝科物种均如此。不对称的程度在物种之间有所不同，与分类亲缘关系没有显著相关性。栖息地类型、深度和大小类在观察到的不对称中具有混杂的影响，没有明显的对应关系。性腺长度的方向性不对称是海鳝科中一种独特且广泛存在的现象，它可能是进化历史中的副产品，在生存方面没有明显的劣势。
