tailieunhanh - Báo cáo y học: "Patterns of intron sequence evolution in Drosophila are dependent upon length and GC conten"

Tuyển tập các báo cáo nghiên cứu về y học được đăng trên tạp chí y học Wertheim cung cấp cho các bạn kiến thức về ngành y đề tài: Patterns of intron sequence evolution in Drosophila are dependent upon length and GC content. | Research Open Access Patterns of intron sequence evolution in Drosophila are dependent upon length and GC content Penelope R Haddrill Brian Charlesworth Daniel L Halligan and Peter Andolfatto Addresses Institute of Evolutionary Biology School of Biological Sciences University of Edinburgh Edinburgh EH9 3JT UK. ỶSection of Ecology Behavior and Evolution Division of Biological Sciences University of California San Diego La Jolla CA 92093 USA. Correspondence Penelope RHaddrill. E-mail Published 27 July 2005 Genome Biology 2005 6 R67 doi 186 gb-2005-6-8-r67 The electronic version of this article is the complete one and can be found online at http 2005 6 8 R67 Received 4 March 2005 Revised 25 April 2005 Accepted 29 June 2005 2005 Haddrill et al. licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License http licenses by which permits unrestricted use distribution and reproduction in any medium provided the original work is properly cited. Abstract Background Introns comprise a large fraction of eukaryotic genomes yet little is known about their functional significance. Regulatory elements have been mapped to some introns though these are believed to account for only a small fraction of genome wide intronic DNA. No consistent patterns have emerged from studies that have investigated general levels of evolutionary constraint in introns. Results We examine the relationship between intron length and levels of evolutionary constraint by analyzing inter-specific divergence at 225 intron fragments in Drosophila melanogaster and Drosophila simulans sampled from a broad distribution of intron lengths. We document a strongly negative correlation between intron length and divergence. Interestingly we also find that divergence in introns is negatively correlated with GC content. This relationship does not account for the correlation between .