Research

Hominoid chromosomal rearrangements on 17q map to complex regions of segmental duplication

Maria Francesca Cardone¹ , Zhaoshi Jiang^2,3 , Pietro D'Addabbo¹ , Nicoletta Archidiacono¹ , Mariano Rocchi¹ , Evan E Eichler^2,3 and Mario Ventura¹

¹Department of Genetics and Microbiology, University of Bari, Via Amendola, Bari, 70126, Italy

²Department of Genome Sciences, University of Washington School of Medicine and the Howard Hughes Medical Institute, NE Pacific Street, Seattle, Washington, 98195, USA

³Howard Hughes Medical Institute, NE Pacific Street, Seattle, Washington, 98195, USA

author email corresponding author email

Genome Biology 2008, 9:R28doi:10.1186/gb-2008-9-2-r28

Published:	7 February 2008

Subject areas: Genetics, Molecular biology, Evolution

Abstract

Background

Chromosomal rearrangements, such as translocations and inversions, are recurrent phenomena during evolution, and both of them are involved in reproductive isolation and speciation. To better understand the molecular basis of chromosome rearrangements and their part in karyotype evolution, we have investigated the history of human chromosome 17 by comparative fluorescence in situ hybridization (FISH) and sequence analysis.

Results

Human bacterial artificial chromosome/p1 artificial chromosome probes spanning the length of chromosome 17 were used in FISH experiments on great apes, Old World monkeys and New World monkeys to study the evolutionary history of this chromosome. We observed that the macaque marker order represents the ancestral organization. Human, chimpanzee and gorilla homologous chromosomes differ by a paracentric inversion that occurred specifically in the Homo sapiens/Pan troglodytes/Gorilla gorilla ancestor. Detailed analyses of the paracentric inversion revealed that the breakpoints mapped to two regions syntenic to human 17q12/21 and 17q23, both rich in segmental duplications.

Conclusion

Sequence analyses of the human and macaque organization suggest that the duplication events occurred in the catarrhine ancestor with the duplication blocks continuing to duplicate or undergo gene conversion during evolution of the hominoid lineage. We propose that the presence of these duplicons has mediated the inversion in the H. sapiens/P. troglodytes/G. gorilla ancestor. Recently, the same duplication blocks have been shown to be polymorphic in the human population and to be involved in triggering microdeletion and duplication in human. These results further support a model where genomic architecture has a direct role in both rearrangement involved in karyotype evolution and genomic instability in human.