Goes Caio Augusto Gomes, Silva Duílio Mazzoni Zerbinato de Andrade, Utsunomia Ricardo, Yasui George Shigueki, Artoni Roberto Ferreira, Foresti Fausto, Porto-Foresti Fábio
Universidade Estadual Paulista "Júlio de Mesquita Filho" (UNESP), Faculdade de Ciências, Bauru, SP, Brazil.
Universidade Estadual Paulista "Júlio de Mesquita Filho" (UNESP), Instituto de Biociências, Botucatu, SP, Brazil.
Genet Mol Biol. 2021 Mar 26;44(2):e20200003. doi: 10.1590/1678-4685-GMB-2020-0003. eCollection 2021.
Supernumerary, or B, chromosomes are present in several eukaryotes, including characid fish of the genus Psalidodon. Notably, Psalidodon paranae carries the most studied B chromosome variant, a macro-B chromosome. The origin of this element was determined to be an isochromosome; however, data regarding its inheritance remain unavailable due to methodological barriers such as the lack of an efficient, non-invasive, and rapid protocol for identifying B-carrying individuals that would enable the design of efficient crossing experiments. Thus, in this study, we primarily aimed was to develop two non-invasive and fast (approximately 2 h) methods to identify the presence of B chromosomes in live specimens of P. paranae based on satellite DNA (satDNA) sequences known to be present in this element. The methods include fluorescence in situ hybridization in interphase nuclei and relative gene quantification of satDNAs using quantitative polymerase chain reaction. Our results reveal the efficiency of quick-fluorescence in situ hybridization and quantitative polymerase chain reaction for identifying B-carrying individuals using the proposed satDNA sequences and open up new possibilities to study B chromosomes.
超数染色体，即B染色体，存在于几种真核生物中，包括锯唇脂鲤属的脂鲤科鱼类。值得注意的是，巴拉那锯唇脂鲤携带了研究最多的B染色体变体，即一条大型B染色体。已确定该元件的起源是一条等臂染色体；然而，由于方法上的障碍，如缺乏一种有效、非侵入性且快速的用于识别携带B染色体个体的方案，从而无法设计有效的杂交实验，关于其遗传的数据仍然无法获得。因此，在本研究中，我们的主要目标是开发两种非侵入性且快速（约2小时）的方法，基于已知存在于该元件中的卫星DNA（satDNA）序列，来识别巴拉那锯唇脂鲤活体标本中B染色体的存在。这些方法包括间期核荧光原位杂交和使用定量聚合酶链反应对satDNA进行相对基因定量。我们的结果揭示了使用所提出的satDNA序列通过快速荧光原位杂交和定量聚合酶链反应来识别携带B染色体个体的效率，并为研究B染色体开辟了新的可能性。
