Abstract # 138:

Scheduled for Friday, August 19, 2005 02:50 PM-03:25 PM: Session 12 (Crystal Ballroom) Oral Presentation

A Genome-wide Comparison of Recent Human and Chimpanzee (PAN TROGLODYTES) Segmental Duplications

Z. Cheng and E. E. Eichler
University of Washington, Department of Genomic Sciences, University of Washington, Seattle, WA 98195, USA
     The human genome contains an abundance of large, highly identical duplications and plays a pivotal role in disease process, gene evolution and genome rearrangement. It is unknown whether slow rates of deletion, high rates of duplication or gene conversion are largely responsible for this effect. We present the first global comparison of differences in content of segmental duplication between human and chimpanzee. Combining experimental and computational approaches, we determine that at least ~3 Mb of new genetic material have been fixed within each genome per million years and that these changes have resulted in gene expression differences between the species. We determine that lineage-specific deletion and duplication have contributed equally while post-speciation gene conversion accounts for less than 10% of recent segmental duplication. Lineage-specific hyperexpansion (>100 copies) of particular segments of DNA have resulted in dramatic quantitative differences and alterations in the genome landscape between chimpanzee and human. Almost all of the most extreme differences relate to changes in chromosome structure including the emergence of African great ape subterminal heterochromatin.