Meiotic behavior, transmission and active genes of B chromosomes in the cichlid Astatotilapia latifasciata: new clues about nature, evolution and maintenance of accessory elements

Author(s)

Cardoso, Adauto Lima ; Venturelli, Natalia Bortholazzi ; da Cruz, Irene ; de Sa Patroni, Fabio Malta ; de Moraes, Diogo ; de Oliveira, Rogerio Antonio ; Benavente, Ricardo ; Martins, Cesar

• Document type: Journal article
• Source: Molecular Genetics and Genomics; v. 297, n. 4, p. 17-pg., 2022-06-15.

Abstract

Supernumerary B chromosomes (Bs) are dispensable genetic elements widespread in eukaryotes and are poorly understood mainly in relation to mechanisms of maintenance and transmission. The cichlid Astatotilapia latifasciata can harbor Bs in a range of 0 (named B -) and 1-2 (named B +). The B in A. latifasciata is rich in several classes of repetitive DNA sequences, contains protein coding genes, and affects hosts in diverse ways, including sex-biased effects. To advance in the knowledge about the mechanisms of maintenance and transmission of B chromosomes in A. latifasciata, here, we studied the meiotic behavior in males and transmission rates of A. latifasciata B chromosome. We also analyzed structurally and functionally the predicted B chromosome copies of the cell cycle genes separin-like, tubb1-like and kif11-like. We identified in the meiotic structure relative to the B chromosome the presence of proteins associated with Synaptonemal Complex organization (SMC3, SYCP1 and SYCP3) and found that the B performs self-pairing. These data suggest that isochromosome formation was a step during B chromosome evolution and this element is in a stage of diversification of the two arms keeping the self-pairing behavior to protect the A chromosome complement of negative effects of recombination. Moreover, we observed no occurrence of B-drive and confirmed the presence of cell cycle genes copies in the B chromosome and their transcription in encephalon, muscle and gonads, which can indicates beneficial effects to hosts and contribute to B maintenance. (AU)

• FAPESP's process: 16/03912-9 - Synaptonemal complex organization and meiotic behavior of B chromosomes in Astatotilapia latifasciata
• Grantee: Natália Bortholazzi Venturelli
• Support Opportunities: Scholarships abroad - Research Internship - Doctorate
• FAPESP's process: 15/16661-1 - Sex and B chromosome enigmas: model systems for the study of chromosome and genome evolution
• Grantee: César Martins
• Support Opportunities: Research Projects - Thematic Grants
• FAPESP's process: 13/25234-4 - Meiotic behavior of B chromosomes in the cichlid fish Astatotilapia latifasciata, based on synaptonemal complex and immunocytogenetic analyses
• Grantee: Natália Bortholazzi Venturelli
• Support Opportunities: Scholarships in Brazil - Doctorate
• FAPESP's process: 16/07743-7 - Experimental validation of candidate microRNAs as regulators of tRNA methylation genes over effect of b chromosomes and sex
• Grantee: Adauto Lima Cardoso
• Support Opportunities: Scholarships abroad - Research Internship - Doctorate
• FAPESP's process: 17/07484-4 - Cell culture from Astatotilapia latifasciata and genome assembly of its B chromosome: contributions to the understanding of the effects of supernumerary chromosomes
• Grantee: Adauto Lima Cardoso
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• FAPESP's process: 14/15756-6 - Evaluation of transcriptional activity of genes present in the B chromosome of the cichlid Astatotilapia latifasciata
• Grantee: Fábio Malta de Sá Patroni
• Support Opportunities: Scholarships in Brazil - Scientific Initiation