A variant W chromosome in Centromochlus heckelii (Siluriformes, Auchenipteridae) and the role of repeated DNA in its heteromorphism.

IF 1.7 4区 生物学 Q4 BIOCHEMISTRY & MOLECULAR BIOLOGY
Genetics and Molecular Biology Pub Date : 2025-01-27 eCollection Date: 2025-01-01 DOI:10.1590/1678-4685-GMB-2024-0071
Chrystian Aparecido Grillo Haerter, Patrik Ferreira Viana, Fábio Hiroshi Takagui, Sandro Tonello, Vladimir Pavan Margarido, Daniel Rodrigues Blanco, Josiane Baccarin Traldi, Roberto Laridondo Lui, Eliana Feldberg
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引用次数: 0

Abstract

Centromochlus heckelii has the lowest diploid chromosome number (2n = 46) and the only described heteromorphic sex chromosome system in Auchenipteridae. This study presents a population of C. heckelii from the Central Amazon basin with subtle variations in the karyotype composition and a variant W chromosome with distinct morphology and increased C-positive heterochromatin content. In this population, the W chromosome is subtelocentric, whereas the only previous study on C. heckelii reported a metacentric W chromosome. Constitutive heterochromatin (CH) and accumulation of microsatellite motifs have significantly contributed to this W chromosome enlargement. Notably, this population exhibits numerous interstitial telomeric sites (ITSs). Some of these ITSs might represent genuine chromosomal fusion points due to the reduced 2n; however, additional mechanisms, such as chromosomal inversions, translocations, transpositions, or association with satellite DNA, are likely responsible for this unusual pattern. The 18S rDNA sites were found in both the Z and W chromosomes of all individuals. However, two individuals exhibited an additional 18S rDNA site in a single homologous of the chromosome pair 20, characterizing an intrapopulation polymorphism. The 5S rDNA sites were found in two chromosome pairs, distinguishing this population from other Centromochlinae species and further supporting it as one of the most efficient cytotaxonomic markers within the subfamily.

黑斑拟中央蝽W染色体的变异及重复DNA在其异型性中的作用。
赫氏中心(Centromochlus heckelii)的二倍体染色体数目最少(2n = 46),是目前已知的唯一的雌雄异型性染色体系统。本研究报道了一个来自亚马逊中部盆地的C. heckelii种群,其核型组成发生了微妙的变化,W染色体变异,形态不同,c阳性异染色质含量增加。在这个群体中,W染色体是亚远中心的,而之前对C. heckelii的唯一研究报道了一个稳定中心的W染色体。组成型异染色质(CH)和微卫星基序的积累是W染色体扩大的重要原因。值得注意的是,这个群体表现出许多间质端粒位点(ITSs)。由于2n的减少,其中一些ITSs可能代表真正的染色体融合点;然而,其他机制,如染色体倒位、易位、转位或与卫星DNA的关联,可能是造成这种不寻常模式的原因。18S rDNA位点在所有个体的Z染色体和W染色体上均有发现。然而,两个个体在一对染色体20的单个同源上显示了额外的18S rDNA位点,表征了种群内多态性。在两对染色体上发现了5S rDNA位点,将该种群与其他种区分开来,并进一步支持其作为亚科中最有效的细胞分类标记之一。
本文章由计算机程序翻译,如有差异,请以英文原文为准。
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来源期刊
Genetics and Molecular Biology
Genetics and Molecular Biology 生物-生化与分子生物学
CiteScore
4.20
自引率
4.80%
发文量
111
审稿时长
3 months
期刊介绍: Genetics and Molecular Biology (formerly named Revista Brasileira de Genética/Brazilian Journal of Genetics - ISSN 0100-8455) is published by the Sociedade Brasileira de Genética (Brazilian Society of Genetics). The Journal considers contributions that present the results of original research in genetics, evolution and related scientific disciplines. Manuscripts presenting methods and applications only, without an analysis of genetic data, will not be considered.
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