title: A linkage map for brown trout (Salmo trutta): chromosome homeologies and comparative genome organization with other salmonid fish.
abstract: We report on the construction of a linkage map for brown trout (Salmo trutta) and its comparison with those of other tetraploid-derivative fish in the family Salmonidae, including Atlantic salmon (Salmo salar), rainbow trout (Oncorhynchus mykiss), and Arctic char (Salvelinus alpinus). Overall, we identified 37 linkage groups (2n = 80) from the analysis of 288 microsatellite polymorphisms, 13 allozyme markers, and phenotypic sex in four backcross families. Additionally, we used gene-centromere analysis to approximate the position of the centromere for 20 linkage groups and thus relate linkage arrangements to the physical morphology of chromosomes. Sex-specific maps derived from multiple parents were estimated to cover 346.4 and 912.5 cM of the male and female genomes, respectively. As previously observed in other salmonids, recombination rates showed large sex differences (average female-to-male ratio was 6.4), with male crossovers generally localized toward the distal end of linkage groups. Putative homeologous regions inherited from the salmonid tetraploid ancestor were identified for 10 pairs of linkage groups, including five chromosomes showing evidence of residual tetrasomy (pseudolinkage). Map alignments with orthologous regions in Atlantic salmon, rainbow trout, and Arctic char also revealed extensive conservation of syntenic blocks across species, which was generally consistent with chromosome divergence through Robertsonian translocations.
authors.affiliation: Laboratoire de Génétique des Poissons, INRA, Jouy-en-Josas, France. k.gharbi@bio.gla.ac.uk
authors.forename: Karim
authors.initials: K
authors.lastname: Gharbi
authors.forename: Angélique
authors.initials: A
authors.lastname: Gautier
authors.forename: Roy G
authors.initials: RG
authors.lastname: Danzmann
authors.forename: Sonia
authors.initials: S
authors.lastname: Gharbi
authors.forename: Takashi
authors.initials: T
authors.lastname: Sakamoto
authors.forename: Bjørn
authors.initials: B
authors.lastname: Høyheim
authors.forename: John B
authors.initials: JB
authors.lastname: Taggart
authors.forename: Margaret
authors.initials: M
authors.lastname: Cairney
authors.forename: Richard
authors.initials: R
authors.lastname: Powell
authors.forename: Francine
authors.initials: F
authors.lastname: Krieg
authors.forename: Nobuaki
authors.initials: N
authors.lastname: Okamoto
authors.forename: Moira M
authors.initials: MM
authors.lastname: Ferguson
authors.forename: Lars-Erik
authors.initials: LE
authors.lastname: Holm
authors.forename: René
authors.initials: R
authors.lastname: Guyomard
mesh_terms: D000818:Animals; D002874:Chromosome Mapping; D005260:Female; D008040:Genetic Linkage; D016678:Genome; D008297:Male; D018895:Microsatellite Repeats; D017683:Oncorhynchus / Q000235:genetics; D011995:Recombination, Genetic; D020317:Salmo salar / Q000235:genetics; D012474:Salmon / Q000235:genetics*; D012737:Sex Factors; D013045:Species Specificity