AquaBreeding Project title: “Towards enhanced and sustainable use of genetics and breeding in the European aquaculture industry”




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2. Genetic variability of the species

Wild genetic resources available

The species’ range encompasses Europe, North America, and Greenland [4]. Non-anadromous forms occur in Europe in a few land-locked locations in Norway and Sweden, and throughout the Neva/Lake Ladoga system and Karelia regions of Russia. In North America non-anadromous forms occurred throughout most of the species’ historical range, as far west as Lake Ontario, and remain common throughout Newfoundland, Labrador and northern Quebec. Over the last 150 years anadromous stocks have become extinct in many rivers. Native stocks are no longer present in the Elbe and the Rhine, two of Europe’s largest rivers, or in many rivers draining into the Baltic and in southern England, France and Spain, which previously had abundant salmon runs, and have become extinct in many rivers in the US and southern Canada [4, 5]. The species has been introduced in a number of locations, both within its range and elsewhere [4] but its native range has contracted and fragmented. Most remaining stocks, particularly in the southern part of its range and in the Baltic Sea region, are depressed and many no longer self-sustaining; detailed information, however, is lacking for most river systems where the species still occurs.


Differences between wild and/or domesticated populations

Genetically differentiation from wild populations is expected due to: 1) the effects of limited numbers, non-random selection and sourcing of wild founders, 2) domestication selection, 3) loss of variability by genetic drift (increased by using small numbers of brood fish), and 4) selective breeding for economic traits [6]. Differences have been reported with regard to variation at protein genes, and at mitochondrial and nuclear DNA loci as well as for phenotype variation [7-10]. Molecular studies show reductions in numbers of alleles and mean heterozygosity of up to 50% and differentiation between strains and wild founder populations 2-6 times higher than among wild populations in general. Changes due to domestication and trait selection exist for growth rate, body size, survival, delayed maturity, stress tolerance, temperature tolerance, disease resistance, flesh quality and egg production. Unintentional correlated changes also occur for fitness-related traits including survival, deformity, spawning time, morphology, fecundity and egg viability, aggression, risk-taking behaviour, and growth hormone production. A >100% and 20% genetic gains have been recorded for growth and feed conversion efficiency, respectively after 5-6 generations in one Norwegian farm strain.


Interaction between wild and domesticated stocks

Around 0.5-2 million salmon (0.5-1.6% of production) escape each year into the North Atlantic, ~50% of the wild pre-fishery abundance in the region [11], despite close regulation of farming. Numbers of sexually mature farm salmon returning to rivers in the 1980s and 1990s ranged from 200,000-300,000 and composed up to 80% of salmon in some Norwegian rivers [11]. Escapes generally enter rivers, near to their farm of origin, but some may do so hundreds of kilometres away, where many interbreed with wild fish, with farm females generally more successful than farm males and more hybrid than pure offspring produced. Escapes of juveniles from hatcheries and freshwater cages occur in some areas but their numbers and impact are poorly documented. Both can cause direct genetic effects on wild populations [11].

Predictions of impact based on modelling vary, depending on the assumptions made. In field studies indirect effects are seen due to behavioural, ecological, and disease interactions which can reduce effective sizes of wild populations and increase genetic drift; in particular, competition with farm fish and hybrids, which are larger, may depress wild smolt production [6]. Direct effects occur due to interbreeding. Farm and farm-wild hybrid offspring show substantially reduced lifetime success with poorer survival in freshwater and at sea, causing reduced recruitment of wild fish [6]. When farm escapes are re-occurring, fitness reductions may accumulate and can lead to the extinction of already depressed populations. Change may also occur in the character of wild populations. For example, increases may occur in multi-sea-winter salmon in predominantly grilse populations. However, though more fecund, given their reduced lifetime success, such hybrids do not compensate for the loss of wild recruitment, and still decrease overall population fitness. Such negative consequences may not occur in all situations, but are likely to be widespread. Impacts are expected even if all wild populations were genetically identical as domestication appears to be the main reason for the genetic differences between farm and wild populations.
Inbreeding effects

Estimated inbreeding depression for growth range from 0.6 to 2.6% per 10% increase in inbreeding coefficient [12, 13]. Inbreeding effects were estimated for spinal deformities in Atlantic salmon and found not to be significant [14].



3. Reproduction

Fecundity and main reproductive features

Broodstock are selected from sea sites, and normally moved into freshwater tanks or cages in summer or autumn prior to stripping. Atlantic Salmon has a high fecundity with about 1000 eggs per kg body weight. Eggs are stripped dry, fertilized with milt, water hardened and disinfected prior to transfer to trays or silo systems. Advanced and synchronised spawning in males and females can be assisted with the aid of hormonal injection [15].


Cryopreservation

Limited and varied success has been reported using published protocols in the literature and anecdotally with the cryopreservation of Atlantic salmon milt [16, 17].

Short-term preservation (up to one week) of Atlantic salmon sperm is feasible without altering its motility with the use of fresh oxygen replaced a number of times daily.
Genetic and environmental sex determination, sexual dimorphism

The mechanism of sex determination in salmonids is largely a mystery but would appear to be mostly genetic in origin. Environmental influences, while having a significant effect on maturation, do not alter the sex ratio among salmon farmed together. Recent data has detected a candidate sex-determining locus as part of chromosome 2. For this reason, this large metacentric chromosome is now regarded as the sex chromosome of this species [18].

Information about genes involved in sex control will have important pragmatic applications in developing monosex aquaculture stocks that will reduce the impact of aquaculture on wild stocks. Also the ability to produce all-female Atlantic salmon Salmo salar stocks is very important to salmonid aquaculture in order to achieve consistent growth patterns and prevent genetic pollution within the wild salmon environment.

4. Selection

Genetic variability per trait

A summary of the estimated heritabilities for economically important traits is shown in table 1.



Genetic correlations and undesirable side effects

Significant positive correlations have been reported between growth rate and early sexual maturation [19-22, 24], . This is an undesirable correlation but the strength and indeed the sign of the correlation also depends on when growth/size is recorded in the cycle. Faster growing fish may make the biological decision to attain sexual maturity earlier but fish which have not reached a certain threshold size at a particular size may postpone maturation but may yet grow faster than mature fish in the winter following this decision period. This may explain why the correlations between these traits differ significantly between studies depending on how and when maturation and growth are recorded.

Other negative correlations are between growth rate and fat content [34, 35], this is also highly dependant on the diet and when growth or size is recorded.
G*E interactions

Moderate to low G*E interactions for weight and length have been found in Atlantic salmon studies [36]. Significant G*E interactions were found for early sexual maturity [21]. Very little is known or at least reported for disease or quality traits.


Table 1: Genetic variability per trait. * Estimates pooled over three or four year classes

Trait [Reference]

Estimated Heritability ± standard errors.

Maturity




Age at Maturity [19]

0.480.20

Age at Maturity [20]

0.39*

Age at Maturity [21]

0.160.06

Early maturity [22]

0.34

Normal maturity [22]

0.24

% non-grilse [23]

0.21*

Gonadosomatic index [24]

0.170.09

Weight and Length




Weight, 12 weeks [25]

0.350.29

Weight, 6months [25]

0.400.26

Weight , 2 years at sea [26]

0.31

Weight at slaughter [27]

0.380.15

Gutted body weight [28]

0.360.10

Gutted body weight [29]

0.440.11

Gutted weight [24]

0.340.01

Gutted weight [30]

0.16*

Length at slaughter [27]

0.420.16

Length at slaughter [29]

0.330.10

Disease resistance/Deformity




Resistance to vibrio anguillarum [31]

0.120.05

Resistance to A. salmonicida [2]

0.38 -0.53

Susceptibility to A. salmonicida [1]

0.480.17

Vertebral deformity [32]

0.22-0.36

Resistance to sea lice [33]

0.260.07 (challenge) 0.060.04 (natural)

Carcass quality




Fat content % [34]

0.300.09

Fat content % [35]

0.120.02

Trait [Reference]

Estimated Heritability ± standard errors.

Carcass quality




Fat content % [30]

0.19*

Flesh colour (score 0-5) [34]

0.090.05

Colour (SalmoFan) [35]

0.120.05

Colour (SalmoFan) [30]

0.14*

Colour (Minolta a* value) [35]

0.200.02

Colour (pigment content) [35]

0.070.01

Colour (pigment content) [30]

0.09*

Average belly thickness [34]

0.270.09


Genetic responses, progresses and control lines

Response to selection in 190 day weight in Atlantic salmon was estimated to be to be 2g or 7% per year [37]. Change in the progeny of selected parents compared to that of the control group after two years at sea was 3.6% and 2.7% per year for two year classes. A considerable response was observed for response to individual selection for age at sexual maturation in Atlantic salmon [20] for this trait. The observed difference in mean age at sexual maturity between offspring of parents aged 5 and 5 and parents aged 4 and 4 was 1.03 years (in age at sexual maturity of the offspring).

The Salmon Genetics Research Program developed a selection index combining percent 1+ smolts (S1s), percent non-grilse and fork length using estimates of parameters from a control (not selected) strain from 1985 [23]. The expected percentage of the total genetic gain attributable to gain in fork length after 17 months in seawater was 71.7%, for percent 1+ smolts 4.2%, and for percent non-grilse 25.1%.

The benefits of selecting on a selection index combining several traits can be seen in a study by Friars et al (1993) where they used an index with four traits on early and late run two-sea-winter salmon. The population was pre-selected at market age and a final selection was performed at sexual maturity using two different indices. Significant gains in the offspring of selected parents, expressed in terms of standard deviations, were noted in all traits and on the index (0.57 and 0.71 standard deviations on the index scale for the early and late run stocks). There was a contrast in the response to % S1 smolt§ in the early (1.2) and late (-.08) run populations. The authors suggest this may reflect different genetic correlations in the early and late run populations. There was a correlated weight response to selection on the index which averaged 0.34kg. This response for a non selected trait is due to the high correlation between length and weight traits in general.


Dominance and intraspecific crossing

At present no studies reporting non-additive effects have been published in Atlantic salmon.



5. Polyploidisation and monosexing and hybrids

Triploid induction and performances

Triploidy has been successfully induced in Atlantic salmon, most successfully with the use of hydrostatic pressure [38-41]. Triploid salmon are of great interest due to the possibility to produce sterile fish and hence reduce the problems of early sexual maturation. However, producers are sceptical of this process due to reduced growth rate [38], lower survival [42] and links to jaw deformities [43]. European consumers may also be sceptical due to associations with gene modified organisms and associated marketing difficulties.


Gynogenesis, androgenesis and mitotic clone performances

Survival of gynogenetics generally low and variable compared to controls.

The production of Atlantic salmon gynogenomes by the combined use of a novel method for sperm irradiation and differently timed high hydrostatic pressure shocks is described. Sperm solutions were exposed to UV irradiation in a temperature-controlled flow-through device. Eggs fertilised with such sperm were exposed to shocks of 9500 psi at 30 min or approximately 7 h after fertilisation in order to produce meiotic and mitotic gynogenomes respectively. Yields of meiotic gynogenomes were generally high (up to 95%); those of mitotic gynogenomes were lower (range 2–20%). Analyses of the offspring by ploidy status and fingerprinting confirmed their gynogenetic origin. Small numbers of mitotic gynogenetic fish were grown on for 2 years in fresh and salt water. S1/S2 ratios were lower in gynogenetic fish and mean age at maturity was greater. Of the presumptive gynogenetic fish subjected to destructive sampling (n = 87) all were female [40, 41].

6. Genomics

Atlantic salmon along with all fish of the family Salmonidae shows residual tetraploidity after a duplication event that occurred 25-100 Myr ago [44]. However, rapid chromosome divergence has been observed between different salmonid species, involving Robertsonian changes as well as other structural rearrangements [44]. Hence, the pseudo-tetraploid state is challenging for researchers working with the Atlantic salmon genome. The Atlantic salmon genome has also shown an uncommonly large difference between recombination rates of males and females. The ratio of female recombination rate vs. male recombination rate was 8.26, the highest ratio reported for any vertebrate [45].

The haploid genome of Atlantic salmon consists of 26 chromosomes, weighting 3.27 pg and contains approximately (763) Mb. A first generation microsatellite linkage map containing over 300 markers distributed over 25-27 linkage groups and covering 820 cM (Kosambi function) is now available [49].

A large insert BAC library with a 18x genome coverage is now available [46]. This will greatly aid the identification of genes and genomic regions of interest. The development of this library indicated a pseudo-tetraploidity of the Atlantic salmon genome. This highly redundant BAC library will be an important resource for mapping and sequencing of the Atlantic salmon genome. A number of micro-arrays available with up to 16,000 salmonid ESTs.


Tools to evaluate population genetic variability

The earliest analysis of genetic structure of wild and farmed Atlantic salmon populations relied on mtDNA and allozymes variation [47-50] . These studies were followed by the analysis of microsatellite markers [9, 48, 51], which showed clear differences in genetic variability between wild and farmed populations of Atlantic salmon but not enough to show bottleneck effects in populations. Research is beginning to be published showing the usefulness of SNP markers for both population genetic variability and parentage identification studies [52].


Genetic markers for genealogical traceability

A number of studies have demonstrated the usefulness of microsatellite markers to determine parentage in mixed family aquaculture situations [53, 54]. Many commercial breeding programs now use microsatellite identification to identify family origin of selected fish in family breeding programs (pers. Comm.).


QTL and Marker Assisted Selection

Although limited research has been presented on the subject [55, 56], a considerable amount of work being done presently to identify QTLs associated with important traits particularly IPN resistance (Roslin/Landcatch, AquaGen).


Transgenesis

Atlantic salmon transgenic for growth hormone have been produced in North America by Aquabounty [57]. Early growth is particularly significantly greater than non-transgenic salmon and time to harvest is said to be halved. These fish have not received FDA approval yet and are not available currently other than for research purposes.


References

  1. GJEDREM, T., H. M. GJOEN and G. B., “Genetic-Origin of Norwegian Farmed Atlantic Salmon,” Aquaculture, vol. 98, pp. 41, 1991a.

  2. GJOEN, H. M., T. REFSTIE, O. ULLA and B. GJERDE, “Genetic correlations between survival of Atlantic salmon in challenge and field tests,” Aquaculture, vol. 158, pp. 277, 1997.

  3. FAO, Aquaculture production: quantities 1950-2005 FISHSTAT Plus - Available at: http://www.fao.org/fi/statist/FISOFT/FISHPLUS.as, 2007.

  4. MACCRIMMON, H. R., and G. B.L., “World distribution of Atlantic salmon, Salmo salar,” Journal of the Fisheries Research Board of Canada, vol. 36, pp. 422-457, 1979.

  5. PARRIS, D. L., BEHNKE R.J., GEPHARD S.R., MCCORMICK S.D. and G. H. REEVES, “Why aren’t there more Atlantic salmon (Salmo salar) ?,” Can. J. Fish. Aquat. Sci., vol. 55, pp. 281-287, 1998.

  6. FERGUSON, A., I. A. FLEMING, K. HINDAR, Ø. SKAALA, P. MCGINNITY et al., “The Atlantic salmon: genetics, conservation and management,” pp. 379-383 in Reviews in Fish Biology and Fisheries, edited by E. VERSPOOR, STRADMEYER, L AND NIELSEN, J.L. Blackwell Publishing, Oxford, 2006.

  7. KNOX, D., and E. VERSPOOR, “A Mitochondrial-Dna Restriction-Fragment-Length-Polymorphism of Potential Use For Discrimination of Farmed Norwegian and Wild Atlantic Salmon Populations in Scotland,” Aquaculture, vol. 98, pp. 249-257, 1991.

  8. MJOLNEROD, I. B., U. H. REFSETH, E. KARLSEN, T. BALSTAD, K. S. JAKOBSEN et al., “Genetic differences between two wild and one farmed population of Atlantic salmon (Salmo salar) revealed by three classes of genetic markers,” Hereditas, vol. 127, pp. 239-248, 1997.

  9. NORRIS, A. T., D. G. BRADLEY and E. P. CUNNINGHAM, “Microsatellite genetic variation between and within farmed and wild Atlantic salmon (Salmo salar) populations,” Aquaculture, vol. 180, pp. 247-264, 1999.

  10. YOUNGSON, A. F., S. A. M. MARTIN, W. C. JORDAN and E. VERSPOOR, “Genetic Protein Variation in Atlantic Salmon in Scotland - Comparison of Wild and Farmed Fish,” Aquaculture, vol. 98, pp. 231-242, 1991.

  11. BENTSEN, H. B., and J. THODESEN., “Genetic interactions between farmed and wild fish, with example from the Atlantic salmon case in Norway in Selection and breeding programs in aquaculture,” edited by T. GJEDREM. Springer, Doordrecht, The Netherlands. pp. 319-334, 1997.

  12. RYE, M., and I. L. MAO, “Non additive genetic effects and inbreeding depression for body weight in Atlantic salmon (Salmo salar L.),” Livestock Production Science, vol. 57, pp. 15, 1998.

  13. KINCAID, H. L., “Inbreeding in fish populations used for aquaculture,” Aquaculture, vol. 33, pp. 215-227, 1983.

  14. BAEVERFJORD, G., ASGARD, T., GJERDE, B. AND HOLMEFJORD, I., “Spinal deformities in Atlantic salmon are neither caused by inbreeding nor a side effect of breeding,” Norsk Fiskeoppdrett, vol. 10, pp. 34-35, 1996.

  15. P. Haffray, W. J. Enright, M. A. Driancourt, T. Mikolajczyk, P. Rault, and B. Breton, "Optimisation of breeding of salmonids: GonazonTM, the first officially approved inducer of ovulation in the UE," World Aquaculture, vol. 36, pp. 52-56, 2005.

  16. ALDERSEN R., and M. N. A. J., “Preliminary investigations of cryopreservation of milt of Atlantic salmon (Salmo salar) and its application to commercial farming,” Aquaculture, vol. 43, pp. 351-355, 1984.

  17. GALLANT, R. K., G. F. RICHARDSON and M. A. MCNIVEN, “Comparison of different extenders for the cryopreservation of Atlantic salmon spermatozoa,” Theriogenology, vol. 40, pp. 479-486, 1993.

  18. ARTIERI, C., L. MITCHELL, S. NG, S. PARISOTTO, R. DANZMANN et al., “Identification of the sex-determining locus of Atlantic salmon (Salmo salar) on chromosome 2”. Cytogen Research, vol. 112, pp. 152-159, 2006.

  19. GLEBE, B. D., and R. L. SAUNDERS, “Genetic factors in sexual maturity of Cultured Atlantic salmon (Salmo salar) parr and adults reared in sea cages,” Can. Spec. Publ. Fish. Aquat. Sci., vol. 89, pp. 24-29, 1986.

  20. GJERDE, B., “Response to individual selection for age at sexual maturity in Atlantic salmon,” Aquaculture, vol. 38, pp. 229-240, 1984.

  21. WILD, V., H. SIMIANER, H. M. GJOEN and B. GJERDE, “Genetic-Parameters and Genotype X Environment Interaction For Early Sexual Maturity in Atlantic Salmon (Salmo Salar),” Aquaculture, vol. 128, pp. 51, 1994.

  22. GJERDE, B., H. SIMIANER and T. REFSTIE, “Estimates of Genetic and Phenotypic Parameters For Body-Weight, Growth-Rate and Sexual Maturity in Atlantic Salmon,” Livestock Production Science, vol. 38, pp. 133, 1994.

  23. O' FLYNN, F. M., G. W. FRIARS, J. K. BAILEY and J. M. TERHUNE, “Development of a Selection Index to Improve Market Value of Cultured Atlantic Salmon (Salmo Salar),” Genome, vol. 35, pp. 304, 1992.

  24. NORRIS, A. T., “Molecular and quantitative analyses of genetic variation in farmed Atlantic salmon”. PhD Thesis, Trinity College Dublin, 2002.

  25. BAILEY, J. K., and E. J. LOUDENSLAGER, “Genetic and environmental components of variation for growth of juvenile Atlantic salmon (Salmo salar)”. Aquaculture, vol. 57, pp. 125-132, 1986.

  26. GUNNES, K., and T. GJEDREM, “Selection experiments with salmon in growth of Atlantic Salmon during two years in the sea,” Aquaculture, vol. 15, pp. 19-33, 1978.

  27. STANDAL, M., and B. GJERDE, “Genetic variation in Survival of Atlantic Salmon during the Sea-Rearing period,” Aquaculture, vol. 66, pp. 197-207, 1987.

  28. RYE, M., and T. REFSTIE, “Phenotypic and genetic parameters of body size traits in Atlantic salmon (Salmo salar),” Aquaculture Research, vol. 26, pp. 876-885, 1995.

  29. GJERDE, B., and T. GJEDREM, “Estimates of Genetic and Phenotypic Parameters For carcass traits in Atlantic Salmon and Rainbow Trout,” Aquaculture, vol. 36, pp. 97-110, 1984.

  30. QUINTON, C. D., I. MCMILLAN and B. D. GLEBE, “Development of an Atlantic salmon (Salmo salar) genetic improvement program: Genetic parameters of harvest body weight and carcass quality traits estimated with animal models,” Aquaculture, vol. 247, pp. 211-217, 2005.

  31. FJALESTAD, K. T., H. J. S. LARSEN and K. H. ROED, “Antibody response in Atlantic salmon (Salmo salar) against Vibrio anguillarum and Vibrio salmonicida O-antigens: Heritabilities, genetic correlations and correlations with survival,” Aquaculture, vol. 145, pp. 77, 1996.

  32. GJERDE, B., M. J. R. PANTE and G. BAEVERFJORD, “Genetic variation for a vertebral deformity in Atlantic salmon (Salmo salar),” Aquaculture, vol. 244, pp. 77-87, 2005.

  33. KOLSTAD, K., P. A. HEUCH, B. GJERDE, T. GJEDREM and R. SALTE, “Genetic variation in resistance of Atlantic salmon (Salmo salar) to the salmon louse Lepeophtheirus salmonis,” Aquaculture, vol. 247, pp. 145-151, 2005.

  34. RYE, M., and B. GJERDE, “Phenotypic and genetic parameters of body composition traits and flesh colour in Atlantic salmon (Salmo salar),” Aquaculture Research, vol. 27, pp. 121-133, 1996.

  35. NORRIS, A. T., and E. P. CUNNINGHAM, 2004 Estimates of phenotypic and genetic parameters for flesh colour traits in farmed Atlantic salmon based on a multiple trait animal model. Livestock Production Science 89, The SAS System 11:11 Tuesday, April 11, 2006.

  36. REFSTIE, T., and T. A. STEINE, “Selection experiments with salmon III. Genetic and environmental sources of variation in length and weight of Atlantic salmon in the freshwater phase,” Aquaculture, vol. 14, pp. 221-234, 1978.

  37. GJEDREM, T., “Genetic variation in quantitative traits and selective breeding in fish and shellfish,” Aquaculture, vol. 33, pp. 51-72, 1983.

  38. OPPEDAL, F., G. LASSE TARANGER and T. HANSEN, “Growth performance and sexual maturation in diploid and triploid Atlantic salmon (Salmo salar L.) in seawater tanks exposed to continuous light or simulated natural photoperiod,” Aquaculture, vol. 215, pp. 145-162, 2003.

  39. JOHNSTONE, R., H. A. MCLAY and M. V. WALSINGHAM, “The production and performance of triploid Atlantic salmon, Salmo salar L.,” in Scotland. Can. Tech. Rep. Fish. Aquat. Sci., vol. 1789, pp. 15-25, 1991.

  40. JOHNSTONE, R., and J. M. STET, “The production of gynogenetic Atlantic salmon, Salmo salar L.,” Theoretical and Applied Genetics, vol. 90, pp. 819-826, 1995a.

  41. JOHNSTONE, R., and R. J. M. STET, “The production of gynogenetic Atlantic salmon, Salmo salar L.,” Theor. Appl.Genet., vol. 90, pp. 819-826, 1995b.

  42. SUTTERLIN, A. M., J. HOLDER and T. J. BENFEY, “Early survival rates and subsequent morphological abnormalities in landlocked, anadromous and hydride diploid and triploid Atlantic salmon,” Aquaculture, vol. 64, pp. 157-164, 1987.

  43. SADLER, J., P. M. PANKHURST and H. R. KING, “High prevalence of skeletal deformity and reduced gill surface area in triploid Atlantic salmon (Salmo salar L.),” Aquaculture, vol. 198, pp. 369-386, 2001.

  44. ALLENDORF, F. W., and G. H. THORGAARD, “Tetraploidy and the evolution of Salmonid fishes,” in Evolutionary genetics of fishes, edited by T. BJ. Plenum Publishing Corporation, New York, 1984.

  45. MOEN, T., B. HøYHEIM, H. MUNCK and L. GOMEZ-RAYA, “A linkage map of Atlantic salmon (Salmo salar) reveals an uncommonly large difference in recombination rate between the sexes,” Anim. Genet., vol. 35, pp. 81-92, 2004.

  46. THORSEN, J., B. ZHU, E. FRENGEN, K. OSOEGAWA, P. J. DE JONG et al., “A highly redundant BAC library of Atlantic salmon (Salmo salar): an important tool for salmon projects,” Genomics, vol. 6, pp. 50, 2005.

  47. BOURKE, E. A., J. COUGHLAN, H. JANSSON, P. GALVIN and T. F. CROSS, “Allozyme variation in populations of Atlantic salmon located throughout Europe: diversity that could be compromised by introductions of reared fish,” Ices Journal of Marine Science, vol. 54, pp. 974-985, 1997.

  48. REILLY, A., N. G. ELLIOTT, P. M. GREWE, C. CLABBY, R. POWELL et al., “Genetic differentiation between Tasmanian cultured Atlantic salmon (Salmo salar L.) and their ancestral Canadian population: comparison of microsatellite DNA and allozyme and mitochondrial DNA variation,” Aquaculture, vol. 173, pp. 459-469, 1999.

  49. TESSIER, N., L. BERNATCHEZ, P. PRESA and B. ANGERS, “Gene Diversity Analysis of Mitochondrial-Dna, Microsatellites and Allozymes in Landlocked Atlantic Salmon,” Journal of Fish Biology, vol. 47, pp. 156-163, 1995.

  50. WILSON, I. F., E. A. BOURKE and T. F. CROSS, “Genetic-Variation At Traditional and Novel Allozyme Loci, Applied to Interactions Between Wild and Reared Salmo Salar L (Atlantic Salmon),” Heredity, vol. 75, pp. 578-588, 1995.

  51. MCCONNELL, S. K. J., D. E. RUZZANTE, P. T. O'REILLY, L. HAMILTON and J. M. WRIGHT, “Microsatellite loci reveal highly significant genetic differentiation among Atlantic salmon (Salmo salar L.) stocks from the east coast of Canada,” Molecular Ecology, vol. 6, pp. 1075-1089, 1997.

  52. RENGMARKA, A. H., A. SLETTANA, O. SKAALAD, O. LIEA and F. LINGAASB, “Genetic variability in wild and farmed Atlantic salmon (Salmo salar) strains estimated by SNP and microsatellites,” Aquaculture, vol. 253, pp. 229-237, 2006.

  53. NORRIS, A. T., D. G. BRADLEY and E. P. CUNNINGHAM, “Parentage and relatedness determination in farmed Atlantic salmon (Salmo salar) using microsatellite markers,” Aquaculture, vol. 182, pp. 73-83, 2000.

  54. O'REILLY, P., T, C. HERBINGER and J. WRIGHT, M, “Analysis of parentage determination in Atlantic salmon (Salmo salar) using microsatellites,” Animal genetics, vol. 29, pp. 363-370, 1998.

  55. HOUSTON, R. D., D. R. GUY, A. HAMILTON, J. RALPH, N. SPRECKLEY et al., “Mapping QTL affecting resistance to infectious pancreatic necrosis (IPN) in Atlantic salmon (Salmo salar),” Aquaculture, vol. 265, 2007.

  56. REID, D. P., A. SZANTO, B. GLEBE, R. G. DANZMANN and M. M. FERGUSON, “QTL for body weight and condition factor in Atlantic salmon (Salmo salar): comparative analysis with rainbow trout (Oncorhynchus mykiss) and Arctic charr (Salvelinus alpinus),” Heredity, vol. 94, pp. 166-172, 2005.

  57. DU, S. J., Z. Y. GONG, G. L. FLETCHER, M. A. SHEARS, M. J. KING et al., “Growth enhancement in transgenic Atlantic salmon by the use of an "all fish" chimeric growth hormone gene construct,” Biotechnology, vol. 10, pp. 176-181, 1992.

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