Bone microstructure and bone mineral density are not systemically different in Antarctic icefishes and related Antarctic notothenioids.
Bone microstructure and bone mineral density are not systemically different in Antarctic icefishes and related Antarctic notothenioids.
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DOI：
10.1111/joa.13537
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发表时间：
2022-01
影响因子：
2.4
通讯作者：
Eames BF
中科院分区：
文献类型：
--
作者：
Ashique AM;Atake OJ;Ovens K;Guo R;Pratt IV;Detrich HW 3rd;Cooper DML;Desvignes T;Postlethwait JH;Eames BF
南极冰鱼（鳅鱼科）的祖先生活在海底，没有鱼鳔，因此从海底升起需要消耗大量能量。为了利用水柱，底栖冰鱼被假设进化出了一种“骨骼减少”的骨骼，这一点得到了总体解剖数据的支持。在这里，我们测试了冰鱼骨骼的变化也发生在大体解剖水平以下的假设。对现存南极鱼类代表性颅面骨（即角骨、额骨、齿骨和关节骨）的组织学和显微 CT 成像专门评估了可能导致“骨质减少”出现的两个特征：骨微结构（例如骨体积分数和结构线密度）和骨矿物质密度（BMD，或每单位骨体积的矿物质质量）。与相关的底栖notothenioids Notothenia coriiceps 和Gobionotothen gibberifrons 相比，冰鱼Chaenocephalus aceratus 和Champsocephalus Gunnari 的骨骼的骨微结构测量结果并不一致。与非冰鱼的同源骨骼相比，一些冰鱼骨骼中的一些定量指标（例如骨体积分数和结构线密度）显着增加。然而，这种差异很少见，而且在所有分析的冰鱼骨骼和物种中，微观结构测量没有一致的差异。此外，冰鱼和非冰鱼南极诺鱼的同源骨骼的 BMD 相似。总之，冰鱼的“骨骼减少”并不是由于骨骼微结构或 BMD 的系统性变化造成的，这表明冰鱼的“骨骼减少”仅发生在总体解剖水平上（即骨骼更小或更少）。鉴于冰鱼与非冰鱼的南极鱼类相比表现出延迟的骨骼发育，将这些表型数据与基因组数据相结合可能会阐明驱动骨骼异时性的遗传变化。南极冰鱼是进化适应的惊人例子。在这里，我们定量地表明，相对于密切相关的鱼类物种，冰鱼骨骼没有改变骨骼微观结构或骨矿物质密度。
Ancestors of the Antarctic icefishes (family Channichthyidae) were benthic and had no swim bladder, making it energetically expensive to rise from the ocean floor. To exploit the water column, benthopelagic icefishes were hypothesized to have evolved a skeleton with “reduced bone,” which gross anatomical data supported. Here, we tested the hypothesis that changes to icefish bones also occurred below the level of gross anatomy. Histology and micro‐CT imaging of representative craniofacial bones (i.e., ceratohyal, frontal, dentary, and articular) of extant Antarctic fish species specifically evaluated two features that might cause the appearance of “reduced bone”: bone microstructure (e.g., bone volume fraction and structure linear density) and bone mineral density (BMD, or mass of mineral per volume of bone). Measures of bone microstructure were not consistently different in bones from the icefishes Chaenocephalus aceratus and Champsocephalus gunnari, compared to the related benthic notothenioids Notothenia coriiceps and Gobionotothen gibberifrons. Some quantitative measures, such as bone volume fraction and structure linear density, were significantly increased in some icefish bones compared to homologous bones of non‐icefish. However, such differences were rare, and no microstructural measures were consistently different in icefishes across all bones and species analyzed. Furthermore, BMD was similar among homologous bones of icefish and non‐icefish Antarctic notothenioids. In summary, “reduced bone” in icefishes was not due to systemic changes in bone microstructure or BMD, raising the prospect that “reduced bone” in icefish occurs only at the gross anatomic level (i.e., smaller or fewer bones). Given that icefishes exhibit delayed skeletal development compared to non‐icefish Antarctic fishes, combining these phenotypic data with genomic data might clarify genetic changes driving skeletal heterochrony. Antarctic icefishes are amazing examples of evolutionary adaptation. Here, we show quantitatively that icefish skeletons did not change bone microstructure or bone mineral density, relative to closely related fish species.