Thousands of human mobile element fragments undergo strong purifying selection near developmental genes

• DOI: 10.1073/pnas.0611223104
• Publication Date: 2007-04-27T00:48:47Z
• Authors: Craig B. Lowe; Gill Bejerano; David Haussler
• Keywords: Negative selection; Conserved sequence; Comparative Genomics

At least 5% of the human genome predating mammalian radiation is thought to have evolved under purifying selection, yet protein-coding and related untranslated exons occupy at most 2% genome. Thus, majority conserved and, by extension, functional sequence in seems be nonexonic. Recent work has highlighted a handful cases where mobile element insertions resulted introduction novel nonexonic elements. Here, we present genome-wide survey 10,402 constrained elements that all been deposited characterized These repeat instances strong selection since boreoeutherian ancestor (100 Mya). They are often located gene deserts show preference for residing closest genes involved development transcription regulation. In particular, with clear repetitive origins near cell adhesion, including cellular members reelin-signaling pathway. Overall, find contributed 5.5% unique mammals, suggesting may played larger role than previously recognized shaping specializing landscape regulation during evolution.