title: Gene expression regulation and lineage evolution: the North and South tale of the hybrid polyploid Squalius alburnoides complex.
abstract: The evolution of hybrid polyploid vertebrates, their viability and their perpetuation over evolutionary time have always been questions of great interest. However, little is known about the impact of hybridization and polyploidization on the regulatory networks that guarantee the appropriate quantitative and qualitative gene expression programme. The Squalius alburnoides complex of hybrid fish is an attractive system to address these questions, as it includes a wide variety of diploid and polyploid forms, and intricate systems of genetic exchange. Through the study of genome-specific allele expression of seven housekeeping and tissue-specific genes, we found that a gene copy silencing mechanism of dosage compensation exists throughout the distribution range of the complex. Here we show that the allele-specific patterns of silencing vary within the complex, according to the geographical origin and the type of genome involved in the hybridization process. In southern populations, triploids of S. alburnoides show an overall tendency for silencing the allele from the minority genome, while northern population polyploids exhibit preferential biallelic gene expression patterns, irrespective of genomic composition. The present findings further suggest that gene copy silencing and variable expression of specific allele combinations may be important processes in vertebrate polyploid evolution.
authors.affiliation: Centro de Biologia Ambiental, Departamento de Biologia Animal, Faculdade de Ciências da Universidade de Lisboa, Lisbon, Portugal. iapala@fc.ul.pt
authors.forename: Irene
authors.initials: I
authors.lastname: Pala
authors.forename: Manfred
authors.initials: M
authors.lastname: Schartl
authors.forename: Miguel
authors.initials: M
authors.lastname: Brito
authors.forename: Joana
authors.initials: J
authors.lastname: Malta Vacas
authors.forename: Maria Manuela
authors.initials: MM
authors.lastname: Coelho
mesh_terms: D000818:Animals; D005075:Biological Evolution; D003530:Cyprinidae / Q000235:genetics* / Q000502:physiology*; D004247:DNA / Q000235:genetics; D003710:Demography; D005260:Female; D020869:Gene Expression Profiling; D005786:Gene Expression Regulation / Q000502:physiology*; D008297:Male; D011123:Polyploidy; D012313:RNA / Q000235:genetics; D045483:Rivers
chemical_list: D012313:RNA; D004247:DNA