Abstract
The human cancer susceptibility gene, BRCA2, functions in double-strand break repair by homologous recombination, and it appears to function via interaction of a repetitive region (“BRC repeats”) with RAD-51. A putatively simpler homolog, dmbrca2, was identified in Drosophila melanogaster recently and also affects mitotic and meiotic double-strand break repair. In this study, we examined patterns of repeat variation both within Drosophila pseudoobscura and among available Drosophila genome sequences. We identified extensive variation within and among closely related Drosophila species in BRC repeat number, to the extent that variation within this genus recapitulates the extent of variation found across the entire animal kingdom. We describe patterns of evolution across species by documenting recent repeat expansions (sometimes in tandem arrays) and homogenizations within available genome sequences. Overall, we have documented patterns and modes of evolution in a new model system of a gene which is important to human health.
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Acknowledgments
The authors thank Callie Barnwell and Lisa Bukovnik (IGSP sequencing center) for technical assistance. Funding was provided by a Research Experience for Undergraduates (REU) supplement from the National Science Foundation (to award 0509780) as well as NSF grant 0715484 and NIH grant GM076051.
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Bennett, S.M., Noor, M.A.F. Molecular evolution of a Drosophila homolog of human BRCA2 . Genetica 137, 213–219 (2009). https://doi.org/10.1007/s10709-009-9376-9
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DOI: https://doi.org/10.1007/s10709-009-9376-9