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Characterization of a swine chromosome-specific centromeric higher-order repeat
M A Janzen1, L B Buoen, F Zhao
1Department of Biochemistry, University of Minnesota, St. Paul, Minnesota 55108, USA.
Summary
Swine centromeres contain higher-order repeats, similar to humans. These repeats, composed of DNA monomers, are chromosome-specific and suggest conserved centromere evolution mechanisms between species.
Area of Science:
- Genomics
- Molecular Biology
- Comparative Genomics
Background:
- Swine centromeric DNA consists of tandemly repeated, divergent monomer units.
- Human centromeres exhibit hierarchical organization of alpha-satellite monomers into higher-order repeats.
Purpose of the Study:
- To investigate the organization of DNA sequences in the swine centromeric region.
- To determine if swine centromeres share hierarchical organizational features with human centromeres.
Main Methods:
- Centromeric cosmid cloning and sequencing.
- Fluorescence in situ hybridization (FISH) analysis.
- Pulsed-field gel electrophoresis (PFGE).
Main Results:
- A 3.3-kb higher-order repeat, composed of ten divergent monomers, was identified in swine centromeres.
- This higher-order repeat is chromosome-specific, localizing to Chromosome 9.
- The swine Chromosome 9 centromeric array spans approximately 2.2 Mb and exhibits EcoRI restriction site polymorphism.
Conclusions:
- Swine centromeres organize divergent satellite sequences into chromosome-specific higher-order repeats, analogous to human centromeres.
- This finding suggests conserved evolutionary mechanisms for creating and maintaining higher-order repeats in vertebrate genomes.