Assignment of Atlantic salmon (Salmo salar) linkage groups to specific chromosomes: conservation of large syntenic blocks corresponding to whole chromosome arms in rainbow trout (Oncorhynchus mykiss).
BACKGROUND
Most teleost species, especially freshwater groups such as the Esocidae which are the closest relatives of salmonids, have a karyotype comprising 25 pairs of acrocentric chromosomes and 48-52 chromosome arms. After the common ancestor of salmonids underwent a whole genome duplication, its karyotype would have 100 chromosome arms, and this is reflected in the modal range of 96-104 seen in extant salmonids (e.g., rainbow trout). The Atlantic salmon is an exception among the salmonids as it has 72-74 chromosome arms and its karyotype includes 12 pairs of large acrocentric chromosomes, which appear to be the result of tandem fusions. The purpose of this study was to integrate the Atlantic salmon's linkage map and karyotype and to compare the chromosome map with that of rainbow trout.


RESULTS
The Atlantic salmon genetic linkage groups were assigned to specific chromosomes in the European subspecies using fluorescence in situ hybridization with BAC probes containing genetic markers mapped to each linkage group. The genetic linkage groups were larger for metacentric chromosomes compared to acrocentric chromosomes of similar size. Comparison of the Atlantic salmon chromosome map with that of rainbow trout provides strong evidence for conservation of large syntenic blocks in these species, corresponding to entire chromosome arms in the rainbow trout.


CONCLUSIONS
It had been suggested that some of the large acrocentric chromosomes in Atlantic salmon are the result of tandem fusions, and that the small blocks of repetitive DNA in the middle of the arms represent the sites of chromosome fusions. The finding that the chromosomal regions on either side of the blocks of repetitive DNA within the larger acrocentric chromosomes correspond to different rainbow trout chromosome arms provides support for this hypothesis.
Phillips
Ruth B
RB
Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada. phillipsr@vancouver.wsu.edu
Keatley
Kimberly A
KA
Morasch
Matthew R
MR
Ventura
Abigail B
AB
Lubieniecki
Krzysztof P
KP
Koop
Ben F
BF
Danzmann
Roy G
RG
Davidson
William S
WS
D000818:Animals; D002874:Chromosome Mapping; D002875:Chromosomes / Q000235:genetics; D055028:Comparative Genomic Hybridization; D019143:Evolution, Molecular; D005260:Female; D008040:Genetic Linkage; D005819:Genetic Markers; D007621:Karyotyping; D008297:Male; D018895:Microsatellite Repeats; D017686:Oncorhynchus mykiss / Q000235:genetics*; D020317:Salmo salar / Q000235:genetics*; D017422:Sequence Analysis, DNA; D026801:Synteny
D005819:Genetic Markers
Nature. 2007 Jun 7;447(7145):714-9
17554307
Genome Res. 2007 Sep;17(9):1254-65
17652425
Cytogenet Cell Genet. 1994;67(1):31-6
8187548
BMC Genomics. 2008 May 15;9:223
18482444
Genome Res. 2003 Feb;13(2):272-80
12566405
Genetics. 1997 Apr;145(4):1083-92
9093860
Genetica. 2006 May;127(1-3):321-7
16850236
Genomics. 2005 Oct;86(4):396-404
16026963
Anim Genet. 2003 Apr;34(2):102-15
12648093
Nucleic Acids Res. 2007 Jan;35(Database issue):D332-8
17090588
Genetics. 2006 Nov;174(3):1661-70
16951085
BMC Genomics. 2005 Apr 04;6:50
15807896
Dev Comp Immunol. 2008;32(3):204-12
17604101
Anim Genet. 2004 Apr;35(2):81-92
15025566
Cytogenet Genome Res. 2006;112(1-2):152-9
16276105
Mol Biol Evol. 2009 May;26(5):1117-25
19221009
Biol Rev Camb Philos Soc. 2001 Feb;76(1):1-25
11325050
BMC Genomics. 2007 Jul 25;8:251
17651474
BMC Genomics. 2008 Apr 28;9:193
18439319
BMC Genomics. 2006 Nov 30;7:302
17137492
BMC Genomics. 2008 Nov 25;9:557
19032764
Chromosoma. 1995 Dec;104(4):242-51
8565700
Anim Genet. 2004 Apr;35(2):98-105
15025568
BMC Genomics. 2008 Aug 28;9:404
18755037
Genome. 2005 Dec;48(6):1037-51
16391673
BMC Genet. 2008 Nov 19;9:74
19019240
Mar Genomics. 2008 Mar;1(1):23-31
21798150