Atukorallaya Devi, Bhatia Vikram, Gonzales Jessica
Department of Oral Biology, Dr. Gerald Niznick College of Dentistry, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, Manitoba R3E0W2, Canada.
Department of Oral Biology, Dr. Gerald Niznick College of Dentistry, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, Manitoba R3E0W2, Canada.
Cells Dev. 2023 Mar;173:203823. doi: 10.1016/j.cdev.2022.203823. Epub 2022 Dec 8.
The Mexican tetra (Astyanax mexicanus) is one of the fresh water teleost fish models in evolutionary developmental biology. The existence of two morphs: eyed, pigmented surface fish and blind depigmented cavefish from multiple cave populations, provides a unique system to study adaptive radiation. Compared to the adult surface fish, cavefish have large oral jaws with an increased number of structurally-complex teeth. Early tooth development has not been studied in detail in cavefish populations. In this study, bone-stained growth series and vital dye staining was used to trace the development and replacement of dentitions in Pachón cavefish. Our results show that first tooth eruption was delayed in cavefish compared to the surface fish. In particular, the first tooth eruption cycle persisted until 35 days post fertilization (dpf). Unlike surface fish, there are multicuspid teeth in cavefish first generation dentition. In addition to the teeth in the marginal oral jaw bones, Pachón cavefish have teeth in the ectopterygoid bone of the palatine roof. Next, we characterised the expression of ectodysplasin signalling pathway genes in tooth-forming regions of surface and cavefish. Interestingly, higher expression of Eda and Edar was found in cavefish compared to the surface fish. The altered ectodysplasin expression needs further investigation to confirm the different molecular mechanisms for tooth development in the oral and pharyngeal regions of surface fish and cavefish.
墨西哥丽脂鲤（Astyanax mexicanus）是进化发育生物学中的淡水硬骨鱼模型之一。它存在两种形态：有眼、有色素的表层鱼，以及来自多个洞穴种群的盲、无色素的洞穴鱼，这为研究适应性辐射提供了一个独特的系统。与成年表层鱼相比，洞穴鱼的口颌较大，结构复杂的牙齿数量增加。洞穴鱼种群的早期牙齿发育尚未得到详细研究。在本研究中，利用骨染色生长序列和活体染料染色来追踪帕琼洞穴鱼牙列的发育和替换。我们的结果表明，与表层鱼相比，洞穴鱼的第一颗牙齿萌出延迟。特别是，第一个牙齿萌出周期持续到受精后35天（dpf）。与表层鱼不同，洞穴鱼第一代牙列中有多尖牙。除了边缘口颌骨中的牙齿外，帕琼洞穴鱼在腭顶的外翼骨中也有牙齿。接下来，我们对表层鱼和洞穴鱼牙齿形成区域外胚层发育不良信号通路基因的表达进行了表征。有趣的是，与表层鱼相比，洞穴鱼中Eda和Edar的表达更高。外胚层发育不良表达的改变需要进一步研究，以确认表层鱼和洞穴鱼口腔和咽部区域牙齿发育的不同分子机制。
