Genomic organization of microsatellites and LINE-1-like retrotransposons: evolutionary implications for Ctenomys minutus (Rodentia: Ctenomyidae) Cytotypes

• Autor(a) principal: Oliveira, Thays Duarte de
• Data de Publicação: 2022
• Outros Autores: Bertocchi, Natasha Ávila, Kretschmer, Rafael, Oliveira, Edivaldo Herculano Corrêa, Cioffi, Marcelo de Bello, Liehr, Thomas, Freitas, Thales Renato Ochotorena de
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Repositório Institucional da UFRGS
• Texto Completo: http://hdl.handle.net/10183/273869
• topic: Roedores subterrâneos; Chromosomal rearrangements; Simple sequence repeats; Retrotransposons

The Neotropical underground rodents of the genus Ctenomys (Rodentia: Ctenomyidae) comprise about 65 species, which harbor the most significant chromosomal variation among mammals (2n = 10 to 2n = 70). Among them, C. minutus stands out with 45 different cytotypes already identified, among which, seven parental ones, named A to G, are parapatrically distributed in the coastal plains of Southern Brazil. Looking for possible causes that led to such extensive karyotype diversification, we performed chromosomal mapping of different repetitive DNAs, including microsatellites and long interspersed element-1 (LINE-1) retrotransposons in the seven parental cytotypes. Although microsatellites were found mainly in the centromeric and telomeric regions of the chromosomes, different patterns occur for each cytotype, thus revealing specific features. Likewise, the LINE-1-like retrotransposons also showed a differential distribution for each cytotype, which may be linked to stochastic loss of LINE-1 in some populations. Here, microsatellite motifs (A)30, (C)30, (CA)15, (CAC)10, (CAG)10, (CGG)10, (GA)15, and (GAG)10 could be mapped to fusion of chromosomes 20/17, fission and inversion in the short arm of chromosome 2, fusion of chromosomes 23/19, and different combinations of centric and tandem fusions of chromosomes 22/24/16. These data provide evidence for a correlation between repetitive genomic content and localization of evolutionary breakpoints and highlight their direct impact in promoting chromosomal rearrangements.