FISH mapping of 45S rRNA and IHHB genes on autosomes and B chromosome of cichlid fish Astatotilapia latifasciata

Autores

  • Maryam Jehangir São Paulo State University
  • Syed Farhan Ahmad São Paulo State University
  • Adauto Lima Cardoso São Paulo State University
  • Guilherme Targino Valente São Paulo State University
  • Cesar Martins São Paulo State University

DOI:

https://doi.org/10.5433/1679-0367.2017v38n1suplp175

Palavras-chave:

Supernumerary chromosome, Genome, Chromosome evolution, Astatotilapia latifasciata

Resumo

B chromosomes (B) are supernumerary, additional and non-homologous to standard (A) chromosomes. Significant biological questions concerning the origin and structural organization of Bs are under discussion. Previous reports found that B chromosomes are enriched with repetitive elements and can carry functional genes. The present study is aimed to extend our knowledge of the structure and composition of B chromosomes. We have combined cytogenetics and genomics approaches to undertsand the B chromosome problem. Cytogenetics analysis, applied to cichlid fish Astatotilapia latifasciata, revealed the presence of 1 or 2 B chromosomes. Next generation sequencing data analysis, based on differential coverage approach, among B- (individual without B) and B+ (individual with B) samples, detected a higher number of copies for the Indian Hedgehog b (Ihhb) gene and 45S RNA transcriptional gene-cluster. Fluorescence in situ hybridization (FISH) confirmed that these genes are located on the B chromosome. In addition, the excessively abundant and strong signals of IHHB on B shows that this gene has accumulated and amplified its copies due to frequent duplication events. The findings also demonstrate that B chromosome have incorporated the entire 45S RNA cluster (18S ribosomal RNA, internal transcribed spacer 1, 5.8S ribosomal RNA, internal transcribed spacer 2, and 28S ribosomal RNA) from the A complement set. Our study contributes to explain that these genic sequences are vital components in constitution of B chromosomes.

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Biografia do Autor

Maryam Jehangir, São Paulo State University

Department of Morphology, Institute of Bioscience, UNESP -São Paulo State University, Botucatu, SP, Brazil

Syed Farhan Ahmad, São Paulo State University

Department of Morphology, Institute of Bioscience, UNESP -São Paulo State University, Botucatu, SP, Brazil

Adauto Lima Cardoso, São Paulo State University

Department of Morphology, Institute of Bioscience, UNESP -São Paulo State University, Botucatu, SP, Brazil

Guilherme Targino Valente, São Paulo State University

Bioprocess and Biotechnology Department, Agronomical Science Faculty, UNESP-São Paulo State University, Botucatu SP, Brazil

Cesar Martins, São Paulo State University

Department of Morphology, Institute of Bioscience, UNESP -São Paulo State University, Botucatu, SP, Brazil

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Publicado

2018-02-16

Como Citar

1.
Jehangir M, Ahmad SF, Cardoso AL, Valente GT, Martins C. FISH mapping of 45S rRNA and IHHB genes on autosomes and B chromosome of cichlid fish Astatotilapia latifasciata. Semin. Cienc. Biol. Saude [Internet]. 16º de fevereiro de 2018 [citado 3º de novembro de 2024];38(1supl):175. Disponível em: https://ojs.uel.br/revistas/uel/index.php/seminabio/article/view/29537