Sex chromosome polymorphisms in Arctic charr and their evolutionary origins

Genome ◽  
2011 ◽  
Vol 54 (10) ◽  
pp. 852-861 ◽  
Author(s):  
Eva Küttner ◽  
Jan Nilsson ◽  
Skúli Skúlason ◽  
Snorri Gunnarsson ◽  
Moira M. Ferguson ◽  
...  

Current data on the Y-specific sex-determining region of salmonid fishes from genera Salvelinus , Salmo , and Oncorhynchus indicate variable polymorphisms in the homologous chromosomal locations of the sex-specific determining region. In the majority of the Atlantic lineage Arctic charr, including populations from the Fraser River, in Labrador Canada, as well as Swedish and Norwegian strains, the sex-determining locus maps to linkage group AC-4. Previously, sex-linked polymorphisms (i.e., variation in the associated sex-linked markers on AC-4) have been described in Arctic charr. Here, we report further evidence for intraspecific sex linkage group polymorphisms in Arctic charr (i.e., the detection of the SEX locus on either the AC-1 or AC-21 linkage group) and a possible conservation of a sex linkage arrangement in Icelandic Arctic charr and Atlantic salmon, involving sex-linked markers on the AC-1/21 homeologs and the European AS-1/6 homeologous linkage groups in Atlantic salmon. The evolutionary origins for the multiple sex-determining regions within the salmonid family are discussed. We also relate the variable sex-determining regions in salmonids to their ancestral proto-teleost karyotypic origins and compare these findings with what has been observed in other teleost species in general.

Genome ◽  
2005 ◽  
Vol 48 (6) ◽  
pp. 1037-1051 ◽  
Author(s):  
Roy G Danzmann ◽  
Margaret Cairney ◽  
William S Davidson ◽  
Moira M Ferguson ◽  
Karim Gharbi ◽  
...  

We updated the genetic map of rainbow trout (Oncorhynchus mykiss) for 2 outcrossed mapping panels, and used this map to assess the putative chromosome structure and recombination rate differences among linkage groups. We then used the rainbow trout sex-specific maps to make comparisons with 2 other ancestrally polyploid species of salmonid fishes, Arctic charr (Salvelinus alpinus) and Atlantic salmon (Salmo salar) to identify homeologous chromosome affinities within each species and ascertain homologous chromosome relationships among the species. Salmonid fishes exhibit a wide range of sex-specific differences in recombination rate, with some species having the largest differences for any vertebrate species studied to date. Our current estimate of female:male recombination rates in rainbow trout is 4.31:1. Chromosome structure and (or) size is associated with recombination rate differences between the sexes in rainbow trout. Linkage groups derived from presumptive acrocentric type chromosomes were observed to have much lower sex-specific differences in recombination rate than metacentric type linkage groups. Arctic charr is karyotypically the least derived species (i.e., possessing a high number of acrocentric chromosomes) and Atlantic salmon is the most derived (i.e., possessing a number of whole-arm fusions). Atlantic salmon have the largest female:male recombination ratio difference (i.e., 16.81:1) compared with rainbow trout, and Arctic charr (1.69:1). Comparisons of recombination rates between homologous segments of linkage groups among species indicated that when significant experiment-wise differences were detected (7/24 tests), recombination rates were generally higher in the species with a less-derived chromosome structure (6/7 significant comparisons). Greater similarity in linkage group syntenies were observed between Atlantic salmon and rainbow trout, suggesting their closer phylogenetic affinities, and most interspecific linkage group comparisons support a model that suggests whole chromosome arm translocations have occurred in the evolution of this group. However, some possible exceptions were detected and these findings are discussed in relation to their influence on segregation distortion patterns. We also report unusual meiotic segregation patterns in a female parent involving the duplicated (homeologous) linkage group pair 12/16 and discuss several models that may account for these patterns.Key words: linkage analysis, genetic markers, polyploidy, tetrasomic inheritance, segregation distortion, recombination rate.


2006 ◽  
Vol 87 (1) ◽  
pp. 33-43 ◽  
Author(s):  
ALEX C. C. WILSON ◽  
PAUL SUNNUCKS ◽  
D. G. BEDO ◽  
J. S. F. BARKER

In drosophilid flies, male recombination and neo-sex chromosome formation are rare. Following the genotyping of full-sib families with 20 microsatellite markers and subsequent cytological work, we found evidence of both male recombination and neo-sex chromosome formation in Scaptodrosophila hibisci. As far as we are aware, this is the first report of male recombination and neo-sex chromosome formation co-occurring in a drosophilid fly. Two autosomal loci, Sh29c and Sh90, showed aberrant segregation of male parental alleles. We describe how an autosomal fission followed by fusion of one of the autosomal fragments to the Y chromosome to create a Y1Y2X1X2/X1X1X2X2 sex determination system provides the most parsimonious explanation of the patterns we observe. Male recombination was observed in three families, including autosomal linkage groups and the Y1/X2 linkage group. In addition to the X1 linkage group, two autosomal linkage groups were identified.


1992 ◽  
Vol 70 (8) ◽  
pp. 1636-1640 ◽  
Author(s):  
Grant E. Brown ◽  
Joseph A. Brown

The purpose of this study was to determine if juvenile Atlantic salmon (Salmo salar) and rainbow trout (Oncorhynchus mykiss) can discriminate kin from non-kin, since other salmonid species (coho salmon (Oncorhynchus kisutch) and Arctic charr (Salvelinus alpinus)) have been shown to possess this ability. When tested in water conditioned by conspecifics (kin and non-kin) and heterospecifics in a two-choice tank, both rainbow trout and Atlantic salmon demonstrated a significant preference for kin over non-kin and heterospecifics, indicating that these species possess kin-discrimination abilities. This ability appears to be widespread among salmonid fishes.


Genetics ◽  
1993 ◽  
Vol 133 (4) ◽  
pp. 865-874
Author(s):  
J A Holmes ◽  
D E Johnson ◽  
S K Dutcher

Abstract Linkage group XIX (or the UNI linkage group) of Chlamydomonas reinhardtii has been reported to show a circular meiotic recombination map. A circular map predicts the existence of strong chiasma and chromatid interference, which would lead to an excess number of two-strand double crossovers during meiosis. We have tested this prediction in multipoint crosses. Our results are consistent with a linear linkage group that shows positive chiasma interference and no chromatid interference. Chiasma interference occurs both within arms and across the centromere. Of the original loci that contributed to the circular map, we find that two map to other linkage groups and a third cannot be retested because the mutant strain that defined it has been lost. A second reported unusual property for linkage group XIX was the increase in meiotic recombination with increases in temperature during a period that precedes the onset of meiosis. Although we observed changes in recombination frequencies in some intervals on linkage group XIX in crosses to CC-1952, and in strains heterozygous for the mutation ger1 at 16 degrees, we also show that our strains do not exhibit the previously observed patterns of temperature-sensitive recombination for two different pairs of loci on linkage group XIX. We conclude that linkage group XIX has a linear genetic map that is not significantly different from other Chlamydomonas linkage groups.


Aquaculture ◽  
2007 ◽  
Vol 273 (2-3) ◽  
pp. 227-234 ◽  
Author(s):  
Even Hjalmar Jørgensen ◽  
Øyvind Aas-Hansen ◽  
Shunsuke Moriyama ◽  
Munehico Iwata ◽  
Jo Espen Tau Strand
Keyword(s):  

Genome ◽  
1997 ◽  
Vol 40 (4) ◽  
pp. 544-551 ◽  
Author(s):  
Yonghe Bai ◽  
T. E. Michaels ◽  
K. P. Pauls

Seven hundred and fifty-six random primers were screened with bulks of genomic DNA from common bacterial blight (CBB) resistant and susceptible bean plants. The plants were from a breeding population derived from an interspecific cross between Phaseolus acutifolius and Phaseolus vulgaris. Four RAPD markers, named R7313, RE416, RE49, and R4865, were found to be significantly associated with CBB resistance in this population. Forty-nine molecular markers segregating in the population were clustered into 8 linkage groups by a MAPMAKER linkage analysis. The largest linkage group was 140 cM long and contained 25 marker loci, including marker R4865. Markers R7313, RE416, and RE49 were clustered on another linkage group. A regression analysis indicated that the markers in these two groups together accounted for 81% of the variation in CBB resistance in the population. The addition of another marker, M56810, which was not individually associated with CBB resistance, increased the total contribution to the trait to 87%.Key words: Phaseolus vulgaris L., common bacterial blight (CBB), polymerase chain reaction (PCR), RAPD markers, linkage groups.


1984 ◽  
Vol 26 (6) ◽  
pp. 762-764 ◽  
Author(s):  
Peter S. Dawson

Reindeer (Rd) is a dominant mutation affecting antenna morphology in the tenebrionid flour beetle, Tribolium castaneum. In contrast with most dominant mutants previously described for this species, homozygotes are fully viable, thus making Rd very useful for genetic studies. Rd is tentatively assigned to either linkage group IX or X. Abbreviated appendages (aa), formerly placed in linkage group X, is reassigned to linkage group V on the basis of demonstrated linkage to jet (j).Key words: Tribolium, mutation Rd, linkage, antenna morphology.


Helia ◽  
2000 ◽  
Vol 23 (33) ◽  
pp. 65-76
Author(s):  
V.V. Kirichenko ◽  
V.N. Popov

SUMMARY The genetics of anodal esterase (Est), cathodal esterase (cEst), cathodal acid phosphatase (cAcp) and malate dehydrogenase (Mdh) has been studied in mature seeds and leaves (genetics of cAcp and Mdh has not been studied in leaves) of sunflower (Helianthus annuus L.). A total of ten loci (four loci of anodal esterase, two loci of cathodal esterase, three loci of malate dehydrogenase and one locus of cathodal acid phosphatase) have been identified and described. Five esterase loci (Est1, Est2, Est3, Est4, cEst5), three malate dehydrogenase loci and one locus of cathodal acid phosphatase are expressed in seeds. Three esterase loci (Est2, cEst5 and cEst6) are expressed in leaves. The analysis of linkage between these loci has been made. Two linkage groups have been found. The sequence of the loci in the first linkage group was Mdh2-Est1- Est2-Est3-cEst5. In the second linkage group it was Est4-cAcp1. Linkages have been analyzed between three isoenzymatic loci expressed in leaves and between two loci controlling morphological traits (branched stem and male fertility restoration). The linkage between morphological traits and isoenzymatic loci has not been revealed. It has been revealed in Br-Rf pair.


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