Severtsov Institute of Ecology and Evolution, Russian Academy of Sciences, Leninsky pr. 33, 119071 Moscow, Russia.
Koltzov Institute of Developmental Biology, Russian Academy of Sciences, Vavilova str., 26, 119334 Moscow, Russia.
J Exp Biol. 2023 Jul 1;226(14). doi: 10.1242/jeb.245710. Epub 2023 Jul 20.
Neotropical cichlids demonstrate an enormous diversity of pigment patterns, a morphological trait that plays an important role in adaptation and speciation. It has been suggested that alterations of the activity of the thyroid axis, one of the main endocrine axes regulating fish ontogeny, are involved in the development and diversification of pigment patterns in Neotropical cichlids. To test this hypothesis, we assessed thyroid hormone developmental dynamics and pigment patterning, and experimentally induced hyperthyroidism and hypothyroidism at different developmental stages in the convict cichlid, Amatitlania nigrofasciata, and blue-eye cichlid, Cryptoheros spilurus. We found that the two species display a similar type of coloration development and similar reactions to changes of thyroid hormone level, but species-specific differences in hormonal dynamics and thyroid hormone responsiveness. These findings indicate that thyroid hormone is a necessary but not sufficient signal to induce the transition from larval to juvenile coloration, and is a component of a complex, concerted endocrine cascade that drives skin development.
新热带慈鲷表现出丰富多样的色素模式，这种形态特征在适应和物种形成中起着重要作用。有研究表明，甲状腺轴的活性改变——调节鱼类个体发育的主要内分泌轴之一——可能参与了新热带慈鲷色素模式的发育和多样化。为了验证这一假设，我们评估了甲状腺激素的发育动态和色素模式，并在新热带慈鲷中的棋盘石斑鱼和蓝眼慈鲷的不同发育阶段，通过实验诱导了甲状腺功能亢进和甲状腺功能减退。我们发现，这两个物种表现出相似的颜色发育类型，对甲状腺激素水平变化的反应也相似，但在激素动力学和甲状腺激素反应性方面存在种特异性差异。这些发现表明，甲状腺激素是诱导从幼虫到幼鱼颜色过渡所必需的，但不是充分的信号，并且是驱动皮肤发育的复杂协同内分泌级联反应的一部分。
