Polymorphism of major ribosomal gene chromosomal sites (NOR-phenotypes) in the hybridogenetic fish Squalius alburnoides complex (Cyprinidae) assessed through crossing experiments

Chromosomal locations of major ribosomal sites, i.e. NOR-phenotypes, were assigned in Squalius alburnoides complex using sequential chromomycin A3 (CMA3)- and silver (Ag)-staining. This hybridogenetic Iberian minnow comprises diploid, triploid and tetraploid forms that arose by interspecific hybridi...

Full description

Saved in:
Bibliographic Details
Published in:Genetica 2004-11, Vol.122 (3), p.291-302
Main Authors: Gromicho, Marta, Collares-Pereira, Maria João
Format: Article
Language:English
Subjects:
Animals
Chromomycin A3
Chromosomes
Crosses, Genetic
Cyprinidae
Cyprinidae - genetics
Diploidy
DNA, Ribosomal
Female
Karyotypes
Male
Nucleolus Organizer Region
Polymorphism, Genetic
Polyploidy
Silver
Silver Staining
Squalius alburnoides
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Chromosomal locations of major ribosomal sites, i.e. NOR-phenotypes, were assigned in Squalius alburnoides complex using sequential chromomycin A3 (CMA3)- and silver (Ag)-staining. This hybridogenetic Iberian minnow comprises diploid, triploid and tetraploid forms that arose by interspecific hybridisation between S. pyrenaicus and an unknown species. Inheritance of NOR patterns was studied by means of crossing experiments involving most diploid-polyploid forms of the S. alburnoides complex with identified specific genotype constitution. In all the specimens studied, the NORs were localised in the short arms of submetacentric chromosomes. Although S. pyrenaicus presented only one pair of NOR-bearing chromosomes, the data from experimental crosses evidenced that S. alburnoides complex was characterised by a multiple NOR phenotype composed of one chromosome pair with stable NORs and two chromosome pairs with NOR site polymorphism of presence/absence type. These data suggest that the karyotype of the unknown parental species of the S. alburnoides complex should have a multiple NOR pattern and emphasised the role of the all-male diploid linage in the dynamics and evolutionary potential of the S. alburnoides complex allowing the preservation of the missing ancestor genome. Cross-analyses evidenced that in spite of the high polymorphic nature of NORs in this fish complex, we have no reason to reject the hypothesis that their inheritance patterns were in accordance with Mendelian segregation.
ISSN:0016-6707
1573-6857
DOI:10.1007/s10709-004-1420-1