Molecular cytogenetics and allotetraploidy in the red vizcacha rat, Tympanoctomys barrerae (Rodentia, Octodontidae)
| Autor: | M.H. Gallardo, I. Cebrián, C.A. González |
|---|---|
| Rok vydání: | 2006 |
| Předmět: |
Male
medicine.medical_specialty food.ingredient Nucleolar dominance Rodentia Locus (genetics) Biology DNA Ribosomal Tympanoctomys barrerae Polyploidy Red vizcacha rat Molecular cytogenetics food Meiosis Chromosome Segregation Gene duplication Genetics medicine Animals NORs Genome size Cells Cultured In Situ Hybridization Fluorescence Repetitive Sequences Nucleic Acid Cytogenetics Tympanoctomys Allotetraploidy Karyotyping Ploidy |
| Zdroj: | GENOMICS Artículos CONICYT CONICYT Chile instacron:CONICYT |
| ISSN: | 0888-7543 |
| DOI: | 10.1016/j.ygeno.2006.02.010 |
| Popis: | The theoretical impossibility of polyploidy in mammals was overturned by the discovery of tetraploidy in the red vizcacha rat, Tympanoctomys barrerae (2n = 102). As a consequence of genome duplication, remarkably increased cell dimensions are observed in the spermatozoa and in different somatic cell lines of this species. Locus duplication had been previously demonstrated by in situ PCR and Southern blot analysis of single-copy genes. Here, we corroborate duplication of loci in multiple-copy (major rDNAs) and single-copy (Hoxc8) genes by fluorescence in situ hybridization. We also demonstrate that nucleolar dominance, a large-scale epigenetic silencing phenomenon characteristic of allopolyploids, explains the presence of only one Ag-NOR chromosome pair in T. barrerae. Nucleolar dominance, together with the chromosomal heteromorphism detected in the G-banding pattern and synaptonemal complexes of the species’ diploid-like meiosis, consistently indicates allotetraploidy. Allotetraploidization can coherently explain the peculiarities of gene silencing, cell dimensions, and karyotypic features of T. barrerae that remain unexplained by assuming diploidy and a large genome size attained by the dispersion of repetitive sequences. |
| Databáze: | OpenAIRE |
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