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Structural evolution of the BRCA1 genomic region in primates
Hong Jin1, Joanna Selfe, Caroline Whitehouse
1Division of Medical & Molecular Genetics, GKT Medical School, King's College, London SE1 9RT, UK.
Genomics
|November 10, 2004
Summary
Genomic rearrangements in the BRCA1 region, driven by Alu repeats, created low-copy repeats linked to genomic disorders. This study details 40 million years of evolution, suggesting a causal link between Alu expansion and gene alterations.
Area of Science:
- Genomics
- Evolutionary Biology
- Molecular Biology
Background:
- Segmental duplications and low-copy repeats (LCRs) comprise up to 6% of the human genome.
- LCRs are implicated in over 20 genomic disorders.
- Alu repeat family expansion occurred during primate evolution, potentially linked to duplications.
Purpose of the Study:
- To trace the evolutionary history of the BRCA1 17q21 region over the last 40 million years.
- To investigate the potential causal relationship between Alu repeat expansion and genomic rearrangements.
Main Methods:
- Comparative genomic analysis of the BRCA1 17q21 region across primate species.
- Identification and characterization of gene-conversion-mediated rearrangements.
- Analysis of Alu repeat subfamily expansion dynamics.
Main Results:
- Discovered approximately eight large gene-conversion-mediated rearrangements in the 4 Mb region surrounding BRCA1 over the last 40 million years.
- These rearrangements resulted in the formation of recombinogenic LCRs, the NBR2 gene, duplicated BRCA1/NBR1 promoter, bisected ARF2 gene, and multiple KIAA0563 copies.
- Rearrangement junctions were found within AluS repeats, an Alu subfamily that expanded during this period.
Conclusions:
- The BRCA1 17q21 region underwent significant genomic upheaval over the last 40 million years.
- Evidence suggests a causal link between Alu family expansion and the creation and destruction of transcription units via rearrangements.