Abstract
Ultraconserved elements (UCEs) are DNA sequences that have been perfectly (100%) con¬served for 300-500mil¬lion years. Be¬cause nei¬ther protein cod¬ing, or en¬han¬c¬er, nor tran¬scrip-tion factor bind¬ing, nor pro¬moter regions re¬quire such conservation, the mere ex¬ist¬¬ence of UCEs has been a long de¬bated conun¬drum. We propose that UCEs con¬trib¬ute to ge¬nome integ¬ri¬ty and, hence, may provide a strategy by which otherwise healthy tis¬sues can be culled of cells harboring dele¬te¬¬r¬ious rearrange¬ments. In addition to probing chromosome behavior, the laboratory develops new technologies for visualizing the genome, most recently, at nanometer-level resolution.