Amorim Karlla Danielle Jorge, Costa Gideão Wagner Werneck Félix da, Cioffi Marcelo de Bello, Tanomtong Alongklod, Bertollo Luiz Antônio Carlos, Molina Wagner Franco
Universidade Federal do Rio Grande do Norte, Departamento de Biologia Celular e Genética, Centro de Biociências, Natal, RN, Brazil.
Universidade Federal de São Carlos, Departamento de Genética e Evolução, Laboratório de Citogenética de Peixes, São Carlos, SP, Brazil.
Genet Mol Biol. 2021 Nov 15;44(4):e20210122. doi: 10.1590/1678-4685-GMB-2021-0122. eCollection 2021.
Epinephelidae (groupers) is an astonishingly diverse group of carnivorous fish widely distributed in reef environments around the world, with growing economic importance. The first chromosomal inferences suggested a conservative scenario for the family. However, to date, this has not been validated using biogeographic and phylogenetic approaches. Thus, to estimate karyotype diversification among groupers, eight species from the Atlantic and Indian oceans were investigated using conventional cytogenetic protocols and fluorescence in situ hybridization of repetitive sequences (rDNA, microsatellites, transposable elements). Despite the remarkable persistence of some symplesiomorphic karyotype patterns, such as all species sharing 2n=48 and most preserve a basal karyotype (2n=48 acrocentrics), the chromosomal diversification in the family revealed an unsuspected evolutionary dynamic, where about 40% of the species escape from the ancestral karyotype pattern. These karyotype changes showed a relation with the historical biogeography, likely as a byproduct of the progressive occupancy of new areas (huge diversity of adaptive and speciation conditions). In this context, oceanic regions harboring more recent clades such as those of the Indo-Pacific, exhibited a higher karyotype diversity. Therefore, the karyotype evolution of Epinephelidae fits well with the expansion and geographic contingencies of its clades, providing a more complex and diverse scenario than previously assumed.
石斑鱼科（石斑鱼）是一类极其多样的肉食性鱼类，广泛分布于世界各地的珊瑚礁环境中，且经济重要性与日俱增。最初的染色体推断表明该科的情况较为保守。然而，迄今为止，尚未通过生物地理学和系统发育学方法对此进行验证。因此，为了估计石斑鱼的核型多样化情况，我们使用传统细胞遗传学方案以及重复序列（核糖体DNA、微卫星、转座元件）的荧光原位杂交技术，对来自大西洋和印度洋的8个物种进行了研究。尽管某些共祖核型模式显著持续存在，比如所有物种都有2n = 48，且大多数保留了基本核型（2n = 48个近端着丝粒染色体），但该科的染色体多样化显示出一种意想不到的进化动态，约40%的物种偏离了祖先核型模式。这些核型变化与历史生物地理学存在关联，可能是新区域逐步被占据（适应性和物种形成条件的巨大多样性）的副产品。在此背景下，拥有较新分支（如印度 - 太平洋地区的分支）的海洋区域表现出更高的核型多样性。因此，石斑鱼科的核型进化与其分支的扩张和地理偶然性非常契合，提供了一个比之前设想更为复杂和多样的情况。
