Genome evolution in the fish family salmonidae: generation of a brook charr genetic map and comparisons among charrs (Arctic charr and brook charr) with rainbow trout

BMC Genetics

Research Article

Chris C Wilson¹  Moira M Ferguson²  Joseph D Norman²  Roy G Danzmann²  Hooman K Moghadam³  Evan R Timusk⁴ 

[1] Aquatic Research and Development Section, Ontario Ministry of Natural Resources, Trent University, K9J7B8, Peterborough, Ontario, Canada;Department of Integrative Biology, University of Guelph, N1G 2W1, Guelph, Ontario, Canada;Department of Integrative Biology, University of Guelph, N1G 2W1, Guelph, Ontario, Canada;Department of Zoology, University of Oxford, South Parks Rd., OX1 3PS, Oxford, UK;Department of Integrative Biology, University of Guelph, N1G 2W1, Guelph, Ontario, Canada;Great Lakes Laboratory for Fisheries and Aquatic Sciences, Fisheries and Oceans, P6A 2E5, Sault Ste. Marie, Ontario, Canada;

关键词: whole-genome duplications;    salmonid fishes;    pseudolinkage;    recombination rates;    segregation distortion;    comparative synteny analyses;    homeologies;    duplicated genes;   

DOI  :  10.1186/1471-2156-12-68

 received in 2011-05-13, accepted in 2011-07-28,  发布年份 2011

来源: Springer

【 摘 要 】

BackgroundSalmonids are regarded as 4R derivative species, having experienced 4 whole genome duplication events in their ancestry. Many duplicated chromosome regions still share extensive homology with one another which is maintained primarily through male-based homeologous chromosome pairings during meiosis. The formation of quadrivalents during meiosis leads to pseudolinkage. This phenomenon is more prevalent within 5 of the 12 ancestral teleost linkage groups in salmonids.ResultsWe constructed a genetic linkage map for brook charr and used this in combination with the genetic map from Arctic charr, to make comparisons with the genetic map of rainbow trout. Although not all chromosome arms are currently mapped, some homologous chromosome rearrangements were evident between Arctic charr and brook charr. Notably, 10 chromosome arms in brook charr representing 5 metacentric chromosomes in Arctic charr have undergone rearrangements. Three metacentrics have one arm translocated and fused with another chromosome arm in brook charr to a make a new metacentrics while two metacentrics are represented by 4 acrocentric pairs in brook charr. In two cases (i.e., BC-4 and BC-16), an apparent polymorphism was observed with the identification of both a putative metacentric structure (similar to metacentric AC-4 = BC-4 and a joining of acrocentric AC-16 + one arm of AC-28 = BC-16), as well as two separate acrocentric linkage groups evident in the mapping parents. Forty-six of the expected 50 karyotypic arms could be inter-generically assigned. SEX in brook charr (BC-4) was localized to the same homologous linkage group region as in Arctic charr (AC-4). The homeologous affinities detected in the two charr species facilitated the identification of 20 (expected number = 25) shared syntenic regions with rainbow trout, although it is likely that some of these regions were partial or overlapping arm regions.ConclusionsInter-generic comparisons among 2 species of charr (genus Salvelinus) and a trout (genus Oncorhynchus) have identified that linkage group arm arrangements are largely retained among these species. Previous studies have revealed that up to 7 regions of high duplicate marker retention occur between Salmo species (i.e., Atlantic salmon and brown trout) and rainbow trout, with 5 of these regions exhibiting higher levels of pseudolinkage. Pseudolinkage was detected in the charr species (i.e., BC-1/21, AC-12/27, AC-6/23, = RT-2p/29q, RT-12p/16p, and RT-27p/31p, respectively) consistent with three of the five 'salmonid-specific' pseudolinkage regions. Chromosome arms with the highest number of duplicated markers in rainbow trout are the linkage group arms with the highest retention of duplicated markers in both charr species.

【 授权许可】

Unknown   
© Timusk et al; licensee BioMed Central Ltd. 2011. This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.