On the association between chromosomal rearrangements and genic evolution in humans and chimpanzees
1 Unitat de Biologia Evolutiva Departament de Ciències Experimentals i de la Salut, Departament de Ciències Experimentals i de la Salut. Universitat Pompeu Fabra. Parc de Recerca Biomèdica de Barcelona. Dr. Aiguader 88. 08003 Barcelona. Catalonia, Spain
2 Genes and Disease Program, Center for Genomic Regulation,. Parc de Recerca Biomèdica de Barcelona. Dr. Aiguader 88, 1. 08003 Barcelona. Catalonia, Spain
3 The Center for Applied Genomics. The Hospital for Sick Children. MaRS Centre - East Tower. 101 College Street, Room 14-706. Toronto, Ontario. Canada
4 Research Unit on Biomedical Informatics of IMIM/UPF. Parc de Recerca Biomèdica de Barcelona. Dr. Aiguader 88. 08003 Barcelona. Catalonia, Spain
5 Dipartimento di Genetica e Microbiologia. Universita di Bari, Bari, Italy
6 Institucio Catalana de Recerca i Estudis Avancats (ICREA) and Unitat de Biologia Evolutiva, Departament de Ciències Experimentals i de la Salut, Universitat Pompeu Fabra. Parc de Recerca Biomèdica de Barcelona. Plaça Dr. Aiguader 88. 08003 Barcelona. Catalonia, Spain
7 CIBER Epidemiología y Salud Pública (CIBERESP), Spain
8 Population Genomics Node (GNV8) National Institute for Bioinformatics (INB), Spain
Genome Biology 2007, 8:R230 doi:10.1186/gb-2007-8-10-r230Published: 30 October 2007
The role that chromosomal rearrangements might have played in the speciation processes that have separated the lineages of humans and chimpanzees has recently come into the spotlight. To date, however, results are contradictory. Here we revisit this issue by making use of the available human and chimpanzee genome sequence to study the relationship between chromosomal rearrangements and rates of DNA sequence evolution.
Contrary to previous findings for this pair of species, we show that genes located in the rearranged chromosomes that differentiate the genomes of humans and chimpanzees, especially genes within rearrangements themselves, present lower divergence than genes elsewhere in the genome. Still, there are considerable differences between individual chromosomes. Chromosome 4, in particular, presents higher divergence in genes located within its rearrangement.
A first conclusion of our analysis is that divergence is lower for genes located in rearranged chromosomes than for those in colinear chromosomes. We also report that non-coding regions within rearranged regions tend to have lower divergence than non-coding regions outside them.
These results suggest an association between chromosomal rearrangements and lower non-coding divergence that has not been reported before, even if some chromosomes do not follow this trend and could be potentially associated with a speciation episode. In summary, without excluding it, our results suggest that chromosomal speciation has not been common along the human and chimpanzee lineage.