Pub Date : 2024-03-27DOI: 10.1134/s0032945224700024
C. A. Fernandes, L. C. Balini, M. M. de Rossi Vieira
Abstract
Cytogenetic studies in Sturisoma are rare; this genus had 11 valid species distributed in basins in South America. In this article, we aimed to expand on the cytogenetic data available for Sturisoma, contributing to the record of the karyotype and other chromosomal characteristics of both minor and major ribosomal DNA of S. barbatum from the upper Paraguay River basin. This population had diploid chromosome number 66, a karyotype composed of 20 metacentric, 14 submetacentric, 14 subtelocentric, and 18 acrocentric chromosomes, and a fundamental number of 114 for both sexes. Heterochromatic regions were observed in the short arms of the nucleolus organizer regions (NOR)-bearing chromosome pair. Fluorescence in situ hybridization revealed a single 18S site and multiple 5S ribosomal DNA sites. Data from NORs confirmed the tendency of this family to present simple NORs sites, as well as multiple sites of 5S ribosomal DNA. Pericentric inversions (or other types of centromeric shift) and/or deletions appear essential in the karyotype evolution and differentiation among S. barbatum. The present data are valuable to help in understanding karyotypic evolution in Loricariidae.
摘要对Sturisoma的细胞遗传学研究很少见;该属有11个有效种,分布在南美洲的盆地中。在本文中,我们旨在扩充现有的 Sturisoma 细胞遗传学数据,为记录巴拉圭河上游流域 S. barbatum 的核型及其他染色体特征、小核糖体 DNA 和大核糖体 DNA 做出贡献。该种群的二倍体染色体数为 66,核型由 20 条元中心染色体、14 条亚元中心染色体、14 条次中心染色体和 18 条尖中心染色体组成,雌雄个体的基数均为 114。在含核仁组织区(NOR)的染色体对的短臂上观察到异色区。荧光原位杂交显示了一个 18S 位点和多个 5S 核糖体 DNA 位点。来自 NORs 的数据证实,该家族倾向于出现简单的 NORs 位点以及多个 5S 核糖体 DNA 位点。核周倒位(或其他类型的向心性偏移)和/或缺失似乎是 S. barbatum 核型进化和分化的关键。本研究数据对了解蝙蝠科动物的核型进化很有价值。
{"title":"Cytogenetic Analysis of Sturisoma barbatum (Loricariidae): New Inferences about Karyotypic Diversification of Sturisoma","authors":"C. A. Fernandes, L. C. Balini, M. M. de Rossi Vieira","doi":"10.1134/s0032945224700024","DOIUrl":"https://doi.org/10.1134/s0032945224700024","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>Cytogenetic studies in <i>Sturisoma</i> are rare; this genus had 11 valid species distributed in basins in South America. In this article, we aimed to expand on the cytogenetic data available for <i>Sturisoma,</i> contributing to the record of the karyotype and other chromosomal characteristics of both minor and major ribosomal DNA of <i>S. barbatum</i> from the upper Paraguay River basin. This population had diploid chromosome number 66, a karyotype composed of 20 metacentric, 14 submetacentric, 14 subtelocentric, and 18 acrocentric chromosomes, and a fundamental number of 114 for both sexes. Heterochromatic regions were observed in the short arms of the nucleolus organizer regions (NOR)-bearing chromosome pair. Fluorescence <i>in situ</i> hybridization revealed a single 18S site and multiple 5S ribosomal DNA sites. Data from NORs confirmed the tendency of this family to present simple NORs sites, as well as multiple sites of 5S ribosomal DNA. Pericentric inversions (or other types of centromeric shift) and/or deletions appear essential in the karyotype evolution and differentiation among <i>S. barbatum</i>. The present data are valuable to help in understanding karyotypic evolution in Loricariidae.</p>","PeriodicalId":48537,"journal":{"name":"Journal of Ichthyology","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2024-03-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140316250","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-03-25DOI: 10.1134/s0032945224010053
P. B. Mikheev
Abstract
The analysis results for morphological variability in the Lower Amur grayling Thymallus tugarinae, one of the five species of grayling fish (Thymallinae) inhabiting the Amur River basin has been reported. Overall, 16 samples of juvenile specimens of the same size class, collected in different parts of the habitat area, are analyzed. A discriminant analysis revealed high-level morphological speciation in grayling fish from different rivers, based on the classification accuracy comprising, on average, 96%. The hiatus in a range of morphological traits was revealed, when comparing certain samples. Clustering classified the grayling fish into groups considered morphologically different because of the variable habitat conditions. The fish from the rivers of the Amur River estuary area were well differed from each other by the morphotype, despite the similarity of the rivers conformed to the same comparatively small region. The graylings inhabiting different sections of a large river were more morphologically distinct, than the fish of small rivers isolated from each other. In addition, increases or shift in the limits of variations of the values of the morphological diagnostic traits of the species were revealed.
{"title":"Geographic Variability in Morphological Traits of Lower Amur Grayling Thymallus tugarinae (Salmonidae: Thymallinae)","authors":"P. B. Mikheev","doi":"10.1134/s0032945224010053","DOIUrl":"https://doi.org/10.1134/s0032945224010053","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>The analysis results for morphological variability in the Lower Amur grayling <i>Thymallus tugarinae</i>, one of the five species of grayling fish (Thymallinae) inhabiting the Amur River basin has been reported. Overall, 16 samples of juvenile specimens of the same size class, collected in different parts of the habitat area, are analyzed. A discriminant analysis revealed high-level morphological speciation in grayling fish from different rivers, based on the classification accuracy comprising, on average, 96%. The hiatus in a range of morphological traits was revealed, when comparing certain samples. Clustering classified the grayling fish into groups considered morphologically different because of the variable habitat conditions. The fish from the rivers of the Amur River estuary area were well differed from each other by the morphotype, despite the similarity of the rivers conformed to the same comparatively small region. The graylings inhabiting different sections of a large river were more morphologically distinct, than the fish of small rivers isolated from each other. In addition, increases or shift in the limits of variations of the values of the morphological diagnostic traits of the species were revealed.</p>","PeriodicalId":48537,"journal":{"name":"Journal of Ichthyology","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2024-03-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140302217","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}