RESUMO
This study provides new data on zebrafish chromosomes, obtained from the chromomycin A3-banding pattern and mapping of 18S rRNA genes by fluorescence in situ hybridization (FISH). C-banding and Agstaining were also performed to analyse whether variation in heterochromatin and Ag-nucleolus organizer regions (NORs) exists among various commercially purchased strains. The results provide information on heterochromatin composition and on the existence of interindividual NOR polymorphism and contribute to the construction of an idiogram suitable for gene mapping.
Assuntos
Bandeamento Cromossômico , Hibridização in Situ Fluorescente , RNA Ribossômico 18S/genética , Peixe-Zebra/genética , Animais , Cromomicina A3 , Mapeamento Cromossômico , Feminino , Corantes Fluorescentes , Marcadores Genéticos , Heterocromatina/genética , Cariotipagem , Masculino , Metáfase , Região Organizadora do Nucléolo/genética , Polimorfismo GenéticoRESUMO
Two zebrafish AluI repeats were localized in metaphase chromosomes by means of the primed in situ (PRINS) labeling technique, using oligonucleotide primers based on published sequences. An AT-rich, tandemly repeated, long AluI restriction fragment (RFAL1) labeled the (peri)centromeric regions of all chromosomes. The GC-rich short fragment (RFAS) was found to be localized in the paracentromeric regions of 17 chromosome pairs, which were mostly subtelocentric. The RFAS labeling pattern generally fits the previously described chromomycin A3 (CMA3) staining pattern. The differential composition of heterochromatin in zebrafish chromosomes is discussed.