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Published on: January 3, 2011
Chromosomal evolution in Rattini (Muridae, Rodentia).
Daleen Badenhorst1, Gauthier Dobigny, Filomena Adega
1Evolutionary Genomics Group, Botany and Zoology Department, University of Stellenbosch, Private Bag X1, 7604 Matieland, South Africa.
Summary
Rodent chromosome evolution in the Rattini tribe is slower than in other murids, with conserved genomic features like NOR locations. This study reconstructs the ancestral Rattini karyotype, revealing insights into rodent speciation.
Area of Science:
- Molecular Cytogenetics
- Comparative Genomics
- Rodent Taxonomy
Background:
- The Rattini tribe, including the model species *Rattus norvegicus*, comprises rodents of significant clinical, agricultural, and epidemiological importance.
- Understanding chromosomal evolution within Rattini is crucial for insights into murid rodent diversification and genomic stability.
Purpose of the Study:
- To conduct a comparative molecular cytogenetic analysis of ten Rattini species.
- To investigate chromosome evolution rates and identify conserved/divergent genomic features within the Rattini tribe.
- To reconstruct the putative ancestral karyotype of the Rattini.
Main Methods:
- Chromosome banding techniques were employed across ten Rattini species.
- Cross-species chromosome painting (Zoo-FISH) and BAC-FISH mapping were utilized.
- Phylogenetic analysis incorporated chromosomal characters from *Rattus norvegicus* and *Maxomys surifer*.
Main Results:
- Rattini species exhibit relatively slow to moderate chromosome evolution rates, contrasting with other murid rodents.
- Nucleolar organizer region (NOR) locations are largely conserved, with specific exceptions noted in *Bandicota savilei* and *Niviventer fulvescens*.
- Morphological variations in *Rattus* chromosomes are attributed to pericentric inversions, and a taxon-specific satellite DNA family was identified.
Conclusions:
- The Rattini lineage demonstrates significant chromosomal stability compared to other murid rodents.
- The reconstructed ancestral Rattini karyotype likely consisted of 46 chromosomes, predominantly acrocentric.
- This study provides a framework for understanding karyotype evolution and diversification within the Rattini tribe.
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