Serrano Érica Alves, Utsunomia Ricardo, Scudeller Patrícia Sobrinho, Oliveira Claudio, Foresti Fausto
Departamento de Morfologia, Instituto de Biociências, Universidade Estadual Paulista, Distrito de Rubião Junior, s/n, 18618-970, Botucatu, São Paulo, Brazil.
Comp Cytogenet. 2017 Jan 20;11(1):81-95. doi: 10.3897/CompCytogen.v11i1.10886. eCollection 2017.
B chromosomes are apparently dispensable components found in the genomes of many species that are mainly composed of repetitive DNA sequences. Among the numerous questions concerning B chromosomes, the origin of these elements has been widely studied. To date, supernumerary chromosomes have been identified in approximately 60 species of fish, including species of the genus Reinhardt, 1867 in which these elements appear to have independently originated. In this study, we used molecular cytogenetic techniques to investigate the origin of B chromosomes in a population of Travassos, 1955 and determine their relationship with the extra chromosomes of other species of the genus. The results showed that the B chromosomes of had an intraspecific origin, apparently originated independently in relation to the B chromosomes of Travassos, 1956 Gomes, 1947 and Travassos, 1967, since they do not share specific DNA sequences, as well as their possible ancestral chromosomes and belong to different phylogenetic clades. The shared sequences between the supernumerary chromosomes and the autosommal sm pair indicate the origin of these chromosomes.
B染色体显然是许多物种基因组中可有可无的成分，主要由重复DNA序列组成。在众多关于B染色体的问题中，这些元件的起源已得到广泛研究。迄今为止，已在约60种鱼类中鉴定出超数染色体，包括1867年莱因哈特属的一些物种，在这些物种中这些元件似乎是独立起源的。在本研究中，我们使用分子细胞遗传学技术研究了1955年特拉瓦索斯种群中B染色体的起源，并确定它们与该属其他物种的额外染色体的关系。结果表明，1955年特拉瓦索斯种群的B染色体具有种内起源，显然是相对于1956年特拉瓦索斯、1947年戈麦斯和1967年特拉瓦索斯的B染色体独立起源的，因为它们不共享特定的DNA序列，以及它们可能的祖先染色体，并且属于不同的系统发育分支。超数染色体与常染色体sm对之间的共享序列表明了这些染色体的起源。
