Identification of large-scale human-specific copy number differences by inter-species array comparative genomic hybridization
- 136 Downloads
Copy number differences (CNDs), and the concomitant differences in gene number, have contributed significantly to the genomic divergence between humans and other primates. To assess its relative importance, the genomes of human, common chimpanzee, bonobo, gorilla, orangutan and macaque were compared by comparative genomic hybridization using a high-resolution human BAC array (aCGH). In an attempt to avoid potential interference from frequent intra-species polymorphism, pooled DNA samples were used from each species. A total of 322 sites of large-scale inter-species CND were identified. Most CNDs were lineage-specific but frequencies differed considerably between the lineages; the highest CND frequency among hominoids was observed in gorilla. The conserved nature of the orangutan genome has already been noted by karyotypic studies and our findings suggest that this degree of conservation may extend to the sub-microscopic level. Of the 322 CND sites identified, 14 human lineage-specific gains were observed. Most of these human-specific copy number gains span regions previously identified as segmental duplications (SDs) and our study demonstrates that SDs are major sites of CND between the genomes of humans and other primates. Four of the human-specific CNDs detected by aCGH map close to the breakpoints of human-specific karyotypic changes [e.g., the human-specific inversion of chromosome 1 and the polymorphic inversion inv(2)(p11.2q13)], suggesting that human-specific duplications may have predisposed to chromosomal rearrangement. The association of human-specific copy number gains with chromosomal breakpoints emphasizes their potential importance in mediating karyotypic evolution as well as in promoting human genomic diversity.
KeywordsSegmental Duplication Lymphoblastoid Cell Line Copy Number Gain AQP7 Gene Primate Genome
We thank Antje Kollak, Helene Spöri and Stefanie Raith for technical assistance. This research was funded by the Deutsche Forschungsgemeinschaft (DFG KE 724/2-1). L.A. and X.E. are supported by Genome Spain and the “Generaliyay de Catalunya”.
- Fortna A, Kim Y, MacLaren E, Marshall K, Hahn G, Meltesen L, Brenton M, Hink R, Burgers S, Hernandez-Boussard T, Karimpour-Fard A, Glueck D, McGavran L, Berry R, Pollack J, Sikela JM (2004) Lineage-specific gene duplication and loss in human and great ape evolution. PLoS Biol 2:E207CrossRefPubMedGoogle Scholar
- Horvath JE, Gulden CL, Bailey JA, Yohn C, McPherson JD, Prescott A, Roe BA, de Jong PJ, Ventura M, Misceo D, Archidiacono N, Zhao S, Schwartz S, Rocchi M, Eichler EE (2003) Using a pericentromeric interspersed repeat to recapitulate the phylogeny and expansion of human centromeric segmental duplications. Mol Biol Evol 20:1463–1479CrossRefPubMedGoogle Scholar
- Sebat J, Lakshmi B, Troge J, Alexander J, Young J, Lundin P, Maner S, Massa H, Walker M, Chi M, Navin N, Lucito R, Healy J, Hicks J, Ye K, Reiner A, Gilliam TC, Trask B, Patterson N, Zetterberg A, Wigler M (2004) Large-scale copy number polymorphism in the human genome. Science 305:525–528CrossRefPubMedGoogle Scholar
- Snijders AM, Nowak N, Segraves R, Blackwood S, Brown N, Conroy J, Hamilton G, Hindle AK, Huey B, Kimura K, Law S, Myambo K, Palmer J, Ylstra B, Yue JP, Gray JW, Jain AN, Pinkel D, Albertson DG (2001) Assembly of microarrays for genome-wide measurement of DNA copy number. Nat Genet 29:263–264CrossRefPubMedGoogle Scholar