Molina Wagner Franco, Khensuwan Sudarat, Rosa de Moraes Renata Luiza, de Menezes Cavalcante Sassi Francisco, Werneck Félix da Costa Gideão Wagner, Miguel Davi Zalder, Supiwong Weerayuth, Jantarat Sitthisak, Phintong Krit, Seetapan Kriengkrai, Ditcharoen Sukhonthip, Tanomtong Alongklod, Liehr Thomas, de Bello Cioffi Marcelo
Department of Cell Biology and Genetics, Biosciences Center, Federal University of Rio Grande Do Norte, Natal, Brazil.
Biology Program, Faculty of Science, Khon Kaen University, Muang, Khon Kaen, 40002, Thailand.
Heliyon. 2024 Mar 5;10(6):e27435. doi: 10.1016/j.heliyon.2024.e27435. eCollection 2024 Mar 30.
The butterflyfishes (Chaetodontidae), emblematic inhabitants of coral reef environments, encompass the majority of known coralivorous species and show one of the highest hybridization rates known among vertebrates, making them an important evolutionary model. The vast knowledge about their life history and phylogenetic relationships contrasts with scarce information on their karyotype evolution. Aiming to expand the cytogenetic data of butterflyfishes and evaluate their karyotype evolution in association with evolutionary aspects, we conducted an extensive cytogenetic analysis in 20 species ( and 19 spp.) from the Atlantic and Indo-Pacific regions, comparing the karyotype macrostructure and the arrangement of the 18S and 5S rDNA repetitive DNA classes in their chromosomes. The results demonstrate that butterflyfishes underwent a period of karyotypic stasis, as evidenced by their homoploid and structurally identical basal karyotype, which has 2n = 48 acrocentric chromosomes and is shared by 90% of species. Only (2n = 48; FN = 50) and (2n = 48; FN = 52) stood out because they both had karyotypes that diverged due to pericentric inversions. The microstructural arrays of 18S rDNA and 5S rDNA sequences were primarily comprised by single and independent loci on homologous chromosomes, indicating that there was little reshuffling among sets of orthologue chromosomes of species. Geographical comparisons revealed similar karyotypes between individuals of from the Greater Caribbean and those of the coast of Brazil, corroborating previous data of gene flow through Amazon/Orinoco plume. The conservative chromosomal patterns in the butterflyfishes, likely overcome the limitations related to segregation and pairing of heterospecific complements and reinforce their contribution to the high degree of hybrid viability and introgression in species.
蝴蝶鱼（蝴蝶鱼科）是珊瑚礁环境的标志性居民，包含了大多数已知的食珊瑚物种，并且在脊椎动物中展现出已知的最高杂交率之一，使其成为一个重要的进化模型。关于它们生活史和系统发育关系的大量知识，与它们核型进化方面的稀缺信息形成对比。为了扩展蝴蝶鱼的细胞遗传学数据，并结合进化方面评估它们的核型进化，我们对来自大西洋和印度 - 太平洋地区的20个物种（和19个物种）进行了广泛的细胞遗传学分析，比较了它们染色体的核型宏观结构以及18S和5S rDNA重复DNA类别的排列。结果表明，蝴蝶鱼经历了一个核型停滞期，这由它们的同倍体和结构相同的基础核型所证明，该基础核型有2n = 48条近端着丝粒染色体，90%的物种都具有此核型。只有（2n = 48；FN = 50）和（2n = 48；FN = 52）脱颖而出，因为它们的核型都因臂间倒位而发生了分歧。18S rDNA和5S rDNA序列的微观结构阵列主要由同源染色体上单个且独立的位点组成，这表明物种的直系同源染色体组之间几乎没有重排。地理比较显示，大安的列斯群岛的个体与巴西海岸的个体之间具有相似的核型，这证实了先前关于通过亚马逊/奥里诺科河羽流进行基因流动的数据。蝴蝶鱼保守的染色体模式，可能克服了与异源特异性互补的分离和配对相关的限制，并加强了它们对物种高度杂交活力和基因渗入的贡献。
