From the Department of Biological Sciences, State University of Southwestern Bahia, Jequié, BA, Brazil (Almeida, Nunes, Bitencourt, and Affonso); and Department of Cell Biology and Genetics, Universidade Federal do Rio Grande do Norte, Natal, RN, Brazil (Molina).
J Hered. 2017 Apr 1;108(3):239-253. doi: 10.1093/jhered/esx003.
The wrasses (family Labridae) represent a suitable model to understand chromosomal evolution and to test the efficacy of cytotaxonomy since they display a remarkable karyotypic variation, rarely reported in marine Perciformes, as well as a high number of species and complex systematics. Therefore, we provided new chromosomal data in 5 labrids from South Atlantic (Doratonotus megalepis, Halichoeres dimidiatus, Halichoeres penrosei, Thalassoma noronhanum, and Xyrichtys novacula) and carried out a detailed comparative analysis of karyotypic data in Labridae using multivariate approaches. Basal diploid values (2n = 48) were observed in most of species studied in the present work but D. megalepis (2n = 46), along with distinct karyotype formulae. Single 18S rDNA sites interspersed with GC-rich heterochromatin were also commonly reported except for both Halichoeres species (2 18S rDNA-bearing pairs), following a species-specific pattern. These data show the high rates of chromosomal evolution in wrasses, ranging from microstructural rearrangements to centric fusions. A revision of chromosomal data in Labridae based on multivariate analysis of 74 taxa allowed inferring karyoevolutionary trends within tribes and genera of wrasses. The dendrogram obtained was in agreement with recent systematic hypotheses. In spite of the independent occurrence of some chromosomal rearrangements, karyoevolutionary trends could be identified within tribes of Labridae. Moreover, the karyotypic features are also suitable as cytotaxonomic markers of wrasses.
隆头鱼科（Labridae）的鱼类代表了一个合适的模型，可以用来理解染色体进化，并测试细胞分类学的有效性，因为它们表现出显著的染色体变异，这种变异在海洋鲈形目鱼类中很少见，同时它们还具有大量的物种和复杂的系统发育。因此，我们提供了来自南大西洋的 5 种隆头鱼（Doratonotus megalepis、Halichoeres dimidiatus、Halichoeres penrosei、Thalassoma noronhanum 和 Xyrichtys novacula）的新染色体数据，并使用多元方法对隆头鱼科的染色体数据进行了详细的比较分析。在本研究中，大多数研究的物种都观察到了基本的二倍体值（2n = 48），但 D. megalepis（2n = 46）除外，其具有独特的染色体图谱。除了两个 Halichoeres 物种（具有 2 对 18S rDNA）外，通常还报道了单个 18S rDNA 位点与富含 GC 的异染色质相间的情况，这遵循特定物种的模式。这些数据显示了隆头鱼染色体进化的高速度，从微观结构重排到着丝粒融合。基于对 74 个分类单元的多元分析对隆头鱼科的染色体数据进行了修订，从而推断出了隆头鱼科内各个部落和属的染色体进化趋势。获得的系统发育树与最近的系统发育假说一致。尽管一些染色体重排是独立发生的，但在隆头鱼科的部落内仍可以识别出染色体进化的趋势。此外，染色体特征也可以作为隆头鱼的细胞分类学标记。
