Department of Biology and Marine Biology, University of North Carolina Wilmington, Wilmington, North Carolina, USA.
Department of Developmental and Cell Biology, University of California Irvine, Irvine, California, USA.
Dev Dyn. 2022 Dec;251(12):2001-2014. doi: 10.1002/dvdy.529. Epub 2022 Aug 30.
The shape and size of skeletal elements is determined by embryonic patterning mechanisms as well as localized growth and remodeling during post-embryonic development. Differential growth between endochondral growth plates underlies many aspects of morphological diversity in tetrapods but has not been investigated in ray-finned fishes. We examined endochondral growth rates in the craniofacial skeletons of two cichlid species from Lake Malawi that acquire species-specific morphological differences during postembryonic development and quantified cellular mechanisms underlying differential growth both within and between species.
Cichlid endochondral growth rates vary greatly (50%-60%) between different growth zones within a species, between different stages for the same growth zone, and between homologous growth zones in different species. Differences in cell proliferation and/or cell enlargement underlie much of this differential growth, albeit in different proportions. Strikingly, differences in extracellular matrix production do not correlate with growth rate differences.
Differential endochondral growth drives many aspects of craniofacial morphological diversity in cichlids. Cellular proliferation and enlargement, but not extracellular matrix deposition, underlie this differential growth and this appears conserved in Osteichthyes. Cell enlargement is observed in some but not all cichlid growth zones and the degree to which it occurs resembles slower growing mammalian growth plates.
骨骼元素的形状和大小是由胚胎模式形成机制以及胚胎后发育过程中的局部生长和重塑决定的。在四足动物中，软骨内生长板的差异生长是形态多样性的许多方面的基础，但在硬骨鱼类中尚未得到研究。我们检查了马拉维湖两种慈鲷物种的颅面骨骼中的软骨内生长速度，这些物种在胚胎后发育过程中获得了特定于物种的形态差异，并量化了物种内和物种间差异生长的细胞机制。
慈鲷软骨内生长速度在同一物种的不同生长区之间、同一生长区的不同阶段之间以及不同物种的同源生长区之间差异很大（50%-60%）。细胞增殖和/或细胞增大差异是这种差异生长的主要原因，尽管比例不同。值得注意的是，细胞外基质产生的差异与生长速度的差异不相关。
差异软骨内生长驱动了慈鲷颅面形态多样性的许多方面。细胞增殖和增大，而不是细胞外基质沉积，是这种差异生长的基础，在硬骨鱼中似乎是保守的。在一些但不是所有的慈鲷生长区都观察到细胞增大，其发生的程度类似于生长较慢的哺乳动物生长板。
