title: Segmental duplications in euchromatic regions of human chromosome 5: a source of evolutionary instability and transcriptional innovation.
abstract: Recent analyses of the structure of pericentromeric and subtelomeric regions have revealed that these particular regions of human chromosomes are often composed of blocks of duplicated genomic segments that have been associated with rapid evolutionary turnover among the genomes of closely related primates. In the present study, we show that euchromatic regions of human chromosome 5-5p14, 5p13, 5q13, 5q15-5q21-also display such an accumulation of segmental duplications. The structure, organization and evolution of those primate-specific sequences were studied in detail by combining in silico and comparative FISH analyses on human, chimpanzee, gorilla, orangutang, macaca, and capuchin chromosomes. Our results lend support to a two-step model of transposition duplication in the euchromatic regions, with a founder insertional event at the time of divergence between Platyrrhini and Catarrhini (25-35 million years ago) and an apparent burst of inter- and intrachromosomal duplications in the Hominidae lineage. Furthermore, phylogenetic analysis suggests that the chronology and, likely, molecular mechanisms, differ regarding the region of primary insertion-euchromatic versus pericentromeric regions. Lastly, we show that as their counterparts located near the heterochromatic region, the euchromatic segmental duplications have consistently reshaped their region of insertion during primate evolution, creating putative mosaic genes, and they are obvious candidates for causing ectopic rearrangements that have contributed to evolutionary/genomic instability.
authors.affiliation: Institut de Pharmacologie Moléculaire et Cellulaire Unité Mixte de Recherche-Centre National de la Recherche Scientifique, 06560 Valbonne, France.
authors.forename: Anouk
authors.initials: A
authors.lastname: Courseaux
authors.forename: Florence
authors.initials: F
authors.lastname: Richard
authors.forename: Josiane
authors.initials: J
authors.lastname: Grosgeorge
authors.forename: Christine
authors.initials: C
authors.lastname: Ortola
authors.forename: Agnes
authors.initials: A
authors.lastname: Viale
authors.forename: Claude
authors.initials: C
authors.lastname: Turc-Carel
authors.forename: Bernard
authors.initials: B
authors.lastname: Dutrillaux
authors.forename: Patrick
authors.initials: P
authors.lastname: Gaudray
authors.forename: Jean-Louis
authors.initials: JL
authors.lastname: Nahon
mesh_terms: D000818:Animals; D002873:Chromosome Fragility / Q000235:genetics*; D002874:Chromosome Mapping; D002895:Chromosomes, Human, Pair 5 / Q000235:genetics*; D022041:Euchromatin / Q000235:genetics*; D019143:Evolution, Molecular; D020440:Gene Duplication; D005819:Genetic Markers / Q000235:genetics; D014644:Genetic Variation / Q000235:genetics; D006801:Humans; D005810:Multigene Family / Q000235:genetics; D011323:Primates / Q000235:genetics; D014158:Transcription, Genetic / Q000235:genetics*
chemical_list: D022041:Euchromatin; D005819:Genetic Markers