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  • 1
    Digitale Medien
    Digitale Medien
    Absence of developmental incompatibility in hybrids between rainbow trout and two subspecies of cutthroat trout (1985)
    Springer
    Biochemical genetics 23 (1985), S. 557-570 
    Details
    ISSN: 1573-4927
    Schlagwort(e): interspecific hybrids ; fish ; development ; gene regulation ; rainbow trout ; cutthroat trout
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract We examined the developmental rate of hybrids between rainbow trout (Salmo gairdneri) and two subspecies of cutthroat trout: westslope cutthroat trout (Salmo clarki lewisi) and Yellowstone cutthroat trout (Salmo clarki bouvieri). These taxa show considerable genetic divergence at 42 structural loci encoding enzymes; the mean Nei's d between the rainbow trout and the two species of cutthroat trout is 0.22. We used four measures of developmental rate: time of hatching and yolk resorption, rate of increase in activity of four enzymes, and time of initial detection of seven isozyme loci. The two cutthroat trout subspecies reached hatching and yolk resorption earlier than rainbow trout. Cutthroat trout had higher relative enzyme activities than rainbow trout from deposition of eye pigment to hatching. There was no difference in the rate of increase in enzyme activity or time of initial expression of these loci between these species. Hybrids showed developmental rates intermediate or similar to that of the parental species using all measures. Our results indicate an absence of regulatory and developmental incompatibility between these taxa.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00504290
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  • 2
    Digitale Medien
    Digitale Medien
    Movers and stayers: Genetic analysis of mobility and positioning in hybrids of lake charr,Salvelinus namaycush, and brook charr,S. fontinalis (Pisces, salmonidae) (1983)
    Springer
    Behavior genetics 13 (1983), S. 213-222 
    Details
    ISSN: 1573-3297
    Schlagwort(e): behavior genetics ; mobility ; positioning ; inheritance ; fish
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Psychologie
    Notizen: Abstract The inheritance of mobility and positioning characteristics of F1 and back-cross hybrids of lake charr (Salvelinus namaycush) and brook charr (S. fontinalis) was investigated. Hybrids showed a closer affinity to brook charr for mobility measurements in that they spent more total time stationary in periods of longer duration than did the lake charr. This suggests either a directional dominance or a response to water flow. Lake, brook, and reciprocal hybrid charr held mean positions within the central section of the water column and did not vary significantly from each other in their mean vertical positions. However, there were significant differences in mean horizontal coordinates across charr types in that lake charr and F1 hydrids occupied positions midway along a laboratory stream channel, while brook charr occupied downstream positions. Even though there were no significant differences between the parental species in either means or standard errors of vertical and horizontal positioning, hybrid phenotypes varied significantly from both parents. Reciprocal effects were observed for variability of horizontal positions. A bivariate ANOVA revealed that horizontal measures were of greater importance than vertical measures in discriminating between charr types. It is likely that both genetic and environmental factors are responsible for the characteristic differences in mobility and positioning between brook and lake charr.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01065670
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  • 3
    Digitale Medien
    Digitale Medien
    Developmental rates of heterozygous and homozygous rainbow trout reared at three temperatures (1988)
    Springer
    Biochemical genetics 26 (1988), S. 53-67 
    Details
    ISSN: 1573-4927
    Schlagwort(e): hatching time ; allozymes ; genetic variation ; fitness ; electrophoresis ; salmonid fishes
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract The hatching distributions of rainbow trout (Salmo gairdneri) with different genotypes at eight loci are compared in two experiments with the same strain. Embryos were incubated at temperatures colder (5 and 8°C) and warmer (12°C) than normally experienced by these fish (9.5°C). At hatching, embryos were separated into five hatching groups representing the chronological order of hatching. There is no significant correlation between multilocus heterozygosity and hatching time at any temperature in either experiment. Fish in the middle of the hatching distribution had the highest average heterozygosity. In both experiments, heterozygotes at the majority of loci examined tended to hatch relatively later within the hatching distribution at 12°C than at both 5 and 8°C. Fish with different genotypes atPgm2 andCk1 showed significant differences in hatching time that were consistent between experiments.Ck1 heterozygotes hatched sooner than homozygotes at 8°C but later at 12°C.Pgm2 heterozygotes hatched later than homozygotes at all temperatures and significantly later in four of five cases. At the other loci examined, however, the relative hatching distributions of fish with particular genotypes were not significantly different or repeatable between experiments.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00555488
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  • 4
    Digitale Medien
    Digitale Medien
    Temperature-dependent genotypic selection and embryonic survival of rainbow trout (1988)
    Springer
    Biochemical genetics 26 (1988), S. 69-81 
    Details
    ISSN: 1573-4927
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract The survival of rainbow trout (Salmo gairdneri) with different developmental rates and genotypes at eight polymorphic loci was compared in two experiments. The embryos were reared at temperatures colder (5 and 8°C) and warmer (12°C) than normally experienced by the strain (9.5°C). Embryo survival in five different hatching groups (representing the sequential order of hatching) was compared at 8 and 12°C. Embryos in the center of the hatching distribution (groups 2, 3, and 4) showed a greater survival to yolk sac resorption than those in the extremes (groups 1 and 5). These differences are significant in the embryos reared at 12°C in both experiments. Embryo survival from hatching to yolk sac resorption was poorer at 12 compared to 8°C. In the one experiment where it was examined, significantly fewer embryos hatched at 5 and 12 than at 8°C. Significant deviations from genotypic expectations (based upon parental allele frequencies) were detected in the progeny (23 of 34 cases). In contrast, few deviations from Hardy-Weinberg expectations were detected (5 of 34 cases) when progeny allele frequencies are used. Few significant differences in genotype frequencies were detected among the progeny reared at the different temperatures. This suggests that nonequal contributions of parental gametes rather than differential selection of genotypes account for the deviations from expectations in the progeny.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00555489
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  • 5
    Digitale Medien
    Digitale Medien
    Developmental rate and viability of rainbow trout with a null allele at a lactate dehydrogenase locus (1988)
    Springer
    Biochemical genetics 26 (1988), S. 177-189 
    Details
    ISSN: 1573-4927
    Schlagwort(e): enzyme polymorphism ; developmental rate ; salmonid fishes ; viability ; natural selection ; gene duplication ; null alleles
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract We show that a previously described isozyme polymorphism in rainbow trout(Salmo gairdneri) is the result of an enzymatically inactive (i.e., null) allele(n). Ldh3 null homozygotes(n/n) and heterozygotes(100/n) have reductions of about 20 and 12% in total lactate dehydrogenase (LDH) activity at hatching, respectively. As juveniles,(100/n) fish have reductions in LDH activity of 15, 37, and 21% in brain, heart, and white muscle, respectively. Embryos with differntLdh3 phenotypes from 11 families do not differ significantly in either survival or hatching time. However, a second measure of developmental rate, the amount of malate dehydrogenase (MDH) and phosphoglucomutase (PGM) activity in 33-day-old embryos, suggests that(100/n) embryos develop more slowly than(100/100) embryos. In three of four families examined,(100/n) embryos have significantly lower amounts of total MDH activity (8–10%). In one of these,(100/n) embryos also have significantly lower total PGM activity (15%). These data suggest that the reduction in total LDH activity is associated with small but detectable delays in developmental rate but nondetectable differences in survival to hatching.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00555498
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  • 6
    Digitale Medien
    Digitale Medien
    Adaptive peaks and alternative foraging tactics in brook charr: evidence of short-term divergent selection for sitting-and-waiting and actively searching (1999)
    Springer
    Behavioral ecology and sociobiology 45 (1999), S. 386-395 
    Details
    ISSN: 1432-0762
    Schlagwort(e): Key words Charr ; Divergent selection ; Fish growth Foraging tactics ; Resource polymorphism
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Some recently emerged brook charr (Salvelinus fontinalis) inhabiting still-water pools along the sides of streams are sedentary and eat crustaceans from the lower portion of the water column. Others are more active and eat insects from the upper portion of the water column. We provide evidence that this divergent foraging behavior reflects short-term divergent selection brought about by intraspecific competition in the presence of alternative food sources. Rates of encounters and interactions between individuals were density dependent, and encounter and interaction events were closely timed with prey capture attempts. In addition, aggressive fish made more foraging attempts per minute than nonaggressive fish. Aggressive fish were also either inactive or very active, while nonaggressive fish exhibited intermediate levels of activity. Growth rate potential, an important component of fitness during the early life stages of brook charr, was assessed using tissue concentrations of RNA and found to be highest for sedentary fish and for active fish making frequent foraging attempts, and lower for fish exhibiting intermediate levels of activity. Our findings support contentions that individual behavior plays an important role during initial steps in the evolution of resource polymorphisms.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s002650050575
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  • 7
    Digitale Medien
    Digitale Medien
    Deviation from morphological intermediacy in interstrain hybrids of rainbow trout, Salmo gairdneri (1987)
    Springer
    Environmental biology of fishes 18 (1987), S. 249-256 
    Details
    ISSN: 1573-5133
    Schlagwort(e): Developmental rate ; Genetics ; Inheritance ; Meristic ; Salmonidae
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Synopsis Deviations from morphological intermediacy in six first generation hybrids between three hatchery strains of rainbow trout, raised in a common environment, are reported. Hybrids have higher mean counts of four meristic characters than their maternal parental strain in a significantly greater number of cases (18 out of 24). Furthermore, eight of eleven hybrid indices are not intermediate. These results are discussed in reference to several mechanisms and models proposed to account for observed responses of meristic characters to environmental and genetic influences.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00004878
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  • 8
    Digitale Medien
    Digitale Medien
    The status and distribution of lake sturgeon, Acipenser fulvescens, in the Canadian provinces of Manitoba, Ontario and Quebec: a genetic perspective (1997)
    Springer
    Environmental biology of fishes 48 (1997), S. 299-309 
    Details
    ISSN: 1573-5133
    Schlagwort(e): postglacial recolonization ; anthropogenic influences ; fish ; Acipenseridae ; conservation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Genetic analysis of mitochondrial DNA sequence variation indicates that most of a sample of 396 lake sturgeon, Acipenser fulvescens, from the northern part of their range belonged to either one of two haplotypes. The vast majority of fish from the Great Lakes/St. Lawrence and Mississippi drainages were of a single haplotype while those from the Hudson/James Bay were composed of both haplotypes. This haplotypic distribution suggests that fish from one refugium (possibly Missourian) recolonized the Hudson-James Bay drainage while those from a second (possibly Mississippian) recolonized the Laurentian Great Lakes and St. Lawrence River. Lake sturgeon still inhabit much of their native postglacial distribution in Manitoba, Ontario and Quebec. However, the stresses of commercial overexploitation and habitat alteration, usually through hydroelectric dam construction and operation, have either singly or in tandem brought about the reduction, if not extirpation, of some populations within the range. The largest zone of extirpation and population reduction has occurred in the Lake Winnipeg drainage area, which covers more than one-third of Manitoba. Other areas where populations have been reduced to remnant levels, if not extirpated, include the lower Laurentian Great Lakes of Lake Ontario and Lake Erie. In northern Ontario, lake sturgeon populations whose riverine habitats have been fragmented by two or more dams are substantially reduced from their former levels. In Quebec, more attention has been paid to limiting the exploitive stresses on lake sturgeon populations. Combination of the genetic and status data suggests that both northern and southern populations of lake sturgeon (possibly from two glacial refugia) have been impacted severely from anthropogenic influences.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1007367818353
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  • 9
    Digitale Medien
    Digitale Medien
    Social grouping and genetic variation in common shiners, Notropis cornutus (Pisces, Cyprinidae) (1981)
    Springer
    Environmental biology of fishes 6 (1981), S. 357-360 
    Details
    ISSN: 1573-5133
    Schlagwort(e): Behaviour ; Esterase ; Evolution ; Genetics ; Isozymes ; Stock structure ; Schools ; Starch gel
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Synopsis Heterogeneous gene frequencies of Est-1 across groups ofNotropis cornutus provide evidence of behaviourally imposed restrictions on stock structuring. Positive fixation indices (F1S = 0.056 and F1T = 0.085) were reflected by a deficiency of heterozygotes for pooled groups. The degree of subdivision ofN. cornutus stocks cannot be evaluated with the present evidence. but it is likely that their schooling behaviour is associated with significant genotypic structuring of the species.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00005765
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  • 10
    Digitale Medien
    Digitale Medien
    Restricted behavioural plasticity of juvenile lake charr, Salvelinus namaycush (1983)
    Springer
    Environmental biology of fishes 8 (1983), S. 151-156 
    Details
    ISSN: 1573-5133
    Schlagwort(e): Social behaviour ; Behaviour-genetics ; Food ; Water flow ; Population density ; Trout ; Salmonidae
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Synopsis Manipulation of water velocity, fish density and food ration produced few significant effects on the behaviour or social system of juvenile lake charr (Salvelinus namaycush). Individuals showed consistently low levels of agonistic behaviour and spent more time close to the substrate with increasing water velocity. The restricted behavioural plasticity and potential of this species is contrasted with the much greater range shown by the closely related brook charr (S. fontinalis).
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00005181
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