NOR polymorphism in the Iberian speciesChondrostoma lusitanicum(Pisces: Cyprinidae)

✍ Scribed by Elsa Rodrigues; Maria João Collares-Pereira

• Book ID: 104628991
• Publisher: Springer Netherlands
• Year: 1996
• Tongue: English
• Weight: 337 KB
• Volume: 98
• Category: Article
• ISSN: 0016-6707
• DOI: 10.1007/bf00120219

✦ Synopsis

Chromosomal polymorphism regarding number of NOR sites in the cyprinid fish Chondrostoma lusitanicum was examined using C-banding, silver-staining (Ag), and fluorescent staining with chromomycin A3 (CMA3). The analysis of heterochromatic regions allowed a more precise identification of the centromeric regions and the proposal of a revised haploid chromosome formula (7M: 15S: 3A). We describe variability in the number of NOR regions per genome, number of active NOR sites per cell, and relative size of individual NORs. Individuals expressed two or four NOR-bearing chromosomes. Polymorphism was detected in all the populations studied and sex-related differences were not found. The observed chromosomal NOR phenotypes suggest the occurrence of structural rearrangements during the evolutionary process of this diploid leuciscine cyprinid.