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Evolution of mouse B1 repeats: 7SL RNA folding pattern conserved
D Labuda1, D Sinnett, C Richer
1Service de Génétique Médicale, Hôpital Ste-Justine, Département de Pédiatrie, Université de Montréal, Québec, Canada.
Journal of Molecular Evolution
|May 1, 1991
Summary
Mouse B1 genomic repeats share similarities with human Alu elements, suggesting a common retroposition model. Evolutionary conservation is linked to RNA-level selection, not just DNA sequence changes.
Area of Science:
- Genomics
- Molecular Evolution
- Bioinformatics
Background:
- Mouse B1 genomic repeats were previously classified into six families based on fixation waves.
- This classification aligns with the retroposition model observed in human Alu elements.
- Understanding the evolutionary dynamics of repetitive elements is crucial in genomics.
Purpose of the Study:
- To analyze nucleotide substitution patterns in individual mouse B1 genomic repeats.
- To compare the minimal energy structures of B1 RNAs from different families.
- To investigate the evolutionary relationship between rodent B1 repeats and human Alu elements.
Main Methods:
- Analysis of nucleotide substitutions in B1 genomic repeats relative to family consensus sequences.
- Computational prediction and experimental enzymatic confirmation of B1 RNA secondary structures.
- In vitro transcription of a young B1 family member RNA using T7 RNA polymerase.
Main Results:
- B1 RNA structures retain folding domains homologous to the Alu fragment of 7SL RNA.
- Experimental data confirmed the predicted RNA structures.
- Similarities were observed among 7SL-like retroposons, human Alu, and rodent B1 repeats.
Conclusions:
- Rodent B1 repeats and human Alu elements share evolutionary and structural similarities.
- The evolutionary conservation of B1 family consensus sequences is influenced by selection acting at the RNA level.
- This study provides insights into the molecular mechanisms driving the evolution of repetitive DNA elements.