Nirchio Mauro, Paim Fabilene G, Milana Valentina, Rossi Anna R, Oliveira Claudio
Facultad de Ciencias Agropecuarias, Universidad Técnica de Machala, Machala, Ecuador.
Departamento de Morfologia, Instituto de Biociências, Universidade Estadual Paulista "Júlio de Mesquita Filho", São Paulo, Brazil.
Front Genet. 2018 Feb 5;9:17. doi: 10.3389/fgene.2018.00017. eCollection 2018.
Mullets are very common fishes included in the family Mugilidae, (Mugiliformes), which are characterized by both a remarkably uniform external morphology and internal anatomy. Recently, within this family, different species complexes were molecularly identified within , a genus which is characterized by lineages that sometimes show very different karyotypes. Here we report the results of cytogenetic and molecular analyses conducted on , commonly known as the hospe mullet, from Ecuador. The study aims to verify whether the original described species from the Pacific Ocean corresponds to that identified in the Atlantic Ocean, and to identify species-specific chromosome markers that can add new comparative data about Mugilidae karyotype evolution. The karyotype of from Ecuador is composed of 48 acrocentric chromosomes and shows two active nucleolar organizer regions (NORs). hybridization, using different types of repetitive sequences (rDNAs, U1 snDNA, telomeric repeats) as probes, identified species-specific chromosome markers that have been compared with those of other species of the genus . Cytochrome c oxidase subunit I (COI) sequence analysis shows only 92-93% similarity with sequences previously deposited under this species name in GenBank, all of which were from the Atlantic Ocean. Phylogenetic reconstructions indicate the presence of three well-supported hospe mullet lineages whose molecular divergence is compatible with the presence of distinct species. Indeed, the first lineage includes samples from Ecuador, whereas the other two lineages include the Atlantic samples and correspond to from Brazil and sp. R from Belize/Venezuela. Results here provided reiterate the pivotal importance of an integrative molecular and cytogenetic approach in the reconstruction of the relationships within Mugilidae.
鲻鱼是鲻科（鲻形目）中非常常见的鱼类，其特点是外部形态和内部解剖结构都非常统一。最近，在这个科中，分子鉴定出了不同的物种复合体，该属的特点是谱系有时显示出非常不同的核型。在这里，我们报告了对来自厄瓜多尔的俗称霍斯佩鲻鱼的细胞遗传学和分子分析结果。该研究旨在验证最初描述的来自太平洋的物种是否与在大西洋中鉴定的物种一致，并确定物种特异性的染色体标记，这些标记可以为鲻科核型进化添加新的比较数据。来自厄瓜多尔的鲻鱼核型由48条近端着丝粒染色体组成，并显示出两个活跃的核仁组织区（NORs）。使用不同类型的重复序列（rDNA、U1 snDNA、端粒重复序列）作为探针的杂交，鉴定出了物种特异性的染色体标记，并与该属其他物种的标记进行了比较。细胞色素c氧化酶亚基I（COI）序列分析显示，与之前以该物种名称保存在GenBank中的序列只有92 - 93%的相似性，所有这些序列都来自大西洋。系统发育重建表明存在三个得到充分支持的霍斯佩鲻鱼谱系，它们的分子差异与不同物种的存在相一致。事实上，第一个谱系包括来自厄瓜多尔的样本，而其他两个谱系包括大西洋的样本，分别对应于来自巴西的鲻鱼和来自伯利兹/委内瑞拉的R鲻鱼。这里提供的结果重申了综合分子和细胞遗传学方法在重建鲻科内部关系中的关键重要性。
