title: Gene copy silencing and DNA methylation in natural and artificially produced allopolyploid fish.
abstract: Allelic silencing is an important mechanism for coping with gene dosage changes in polyploid organisms that is well known in allopolyploid plants. Only recently, it was shown in the allotriploid fish Squalius alburnoides that this process also occurs in vertebrates. However, it is still unknown whether this silencing mechanism is common to other allopolyploid fish, and which mechanisms might be responsible for allelic silencing. We addressed these questions in a comparative study between Squalius alburnoides and another allopolyploid complex, the Amazon molly (Poecilia formosa). We examined the allelic expression patterns for three target genes in four somatic tissues of natural allo-anorthoploids and laboratory-produced tri-genomic hybrids of S. alburnoides and P. formosa. Also, for both complexes, we evaluated the correlation between total DNA methylation level and the ploidy status and genomic composition of the individuals. We found that allelic silencing also occurs in other allopolyploid organisms besides the single one that was previously known. We found and discuss disparities within and between the two considered complexes concerning the pattern of allele-specific expression and DNA methylation levels. Disparities might be due to intrinsic characteristics of each genome involved in the hybridization process. Our findings also support the idea that long-term evolutionary processes have an effect on the allele expression patterns and possibly also on DNA methylation levels.
authors.affiliation: Centre for Ecology, Evolution and Environmental Changes, Faculdade de Ciências, Universidade de Lisboa, Lisboa 1749-016, Portugal Department of Physiological Chemistry, Biocenter, University of Würzburg, Würzburg 97078, Germany immatos@fc.ul.pt.
authors.forename: Isa M N
authors.identifier: 0000-0002-3725-6742
authors.initials: IM
authors.lastname: Matos
authors.affiliation: Centre for Ecology, Evolution and Environmental Changes, Faculdade de Ciências, Universidade de Lisboa, Lisboa 1749-016, Portugal.
authors.forename: Maria M
authors.initials: MM
authors.lastname: Coelho
authors.affiliation: Department of Physiological Chemistry, Biocenter, University of Würzburg, Würzburg 97078, Germany Comprehensive Cancer Center Mainfranken, University Clinic Würzburg, Würzburg 97078, Germany Texas Institute for Advanced Study and Department of Biology, Texas A&M University, College Station, TX 77843, USA.
authors.forename: Manfred
authors.initials: M
authors.lastname: Schartl
mesh_terms: D000483:Alleles; D000818:Animals; D018899:CpG Islands / Q000235:genetics; D003530:Cyprinidae / Q000235:genetics*; D019175:DNA Methylation / Q000235:genetics*; D018628:Gene Dosage; D005786:Gene Expression Regulation; D020868:Gene Silencing; D016678:Genome; D009928:Organ Specificity / Q000235:genetics; D011123:Polyploidy; D011401:Promoter Regions, Genetic / Q000235:genetics
keywords: Allelic silencing; Allopolyploidy; DNA methylation; Freshwater fish; Poecilia formosa; Squalius alburnoides