Gene segregation in induced tetraploid rainbow trout: genetic evidence of preferential pairing of homologous chromosomes

Genome ◽  
1988 ◽  
Vol 30 (4) ◽  
pp. 547-553 ◽  
Author(s):  
A. Diter ◽  
R. Guyomard ◽  
D. Chourrout
Keyword(s):  
Rainbow Trout ◽  
Genetic Evidence ◽  
Salmo Gairdneri ◽  
Preferential Pairing ◽  
Homologous Chromosomes ◽  
Tetrasomic Inheritance ◽  
Gene Segregation ◽  
Sib Families ◽  
Males And Females ◽  
Homoeologous Chromosomes

Gene segregation at six protein loci was analysed in progeny from tetraploid males and females obtained by suppression of first mitosis. The triploid full-sib families from five tetraploid males and the diploid gynogenetic lines from four tetraploid females were examined. The proportions of heterozygous gametes (0.83 on the average) were significantly higher than expected from tetrasomic inheritance (0.667) at all the loci studied. This was explained by preferential pairing of homologous chromosomes. The proportions of heterozygous gametes were significantly different between loci, but the variations were not correlated with the gene–centromere distances. Our results showed that, at least for one locus, the homozygous gametes mainly resulted from pairing of homoeologous chromosomes rather than from pairing of homologous chromosomes, quadrivalent formation, and chromatin exchanges between homoeologous chromosomes.Key words: Salmo gairdneri richardson, induced tetraploidy, gene segregation, electrophoresis.

Secondary Tetrasomic Segregation of MDH-B and Preferential Pairing of Homeologues in Rainbow Trout

Genetics ◽  
1997 ◽  
Vol 145 (4) ◽  
pp. 1083-1092 ◽  
Author(s):  
Fred W Allendorf ◽  
Roy G Danzmann
Keyword(s):  
Allelic Variation ◽  
Male Meiosis ◽  
Proximal Region ◽  
Stage Model ◽  
Preferential Pairing ◽  
Homologous Chromosomes ◽  
Tetrasomic Inheritance ◽  
Segregation Ratios ◽  
Homeologous Chromosomes ◽  
Duplicated Loci

We examined the inheritance of allelic variation at an isozyme locus, MDH-B, duplicated by ancestral polyploidy in salmonid fishes. We detected only disomic segregation in females. Segregation ratios in males were best explained by a mixture of disomic and tetrasomic inheritance. We propose a two-stage model of pairing in male meiosis in which, first, homologous chromosomes pair and recombine in the proximal region of the chromosome. Next, homeologous chromosomes pair and recombine distally. We suggest that this type of tetrasomic inheritance in which centromeres segregate disomically should be referred to as “secondary tetrasomy” to distinguish it from tetrasomy involving entire chromosomes (i.e., “primary tetrasomy”). Differences in segregation ratios between males indicate differences between individuals in the amount of recombination between homeologous chromosomes. We also consider the implication of these results for estimation of allele frequencies at duplicated loci in salmonid populations.

Some Chemical Signals in the Spawning Behavior of Rainbow Trout (Salmo gairdneri)

1973 ◽  
Vol 30 (7) ◽  
pp. 995-997 ◽  
Author(s):  
C. Newcombe ◽  
G. Hartman
Keyword(s):  
Rainbow Trout ◽  
Chemical Signals ◽  
Salmo Gairdneri ◽  
Auditory Stimuli ◽  
Spawning Behavior ◽  
Olfactory Information ◽  
Males And Females ◽  
Chemical Stimuli

In a two-choice maze ripe rainbow trout (Salmo gairdneri) of both sexes showed positive responses to chemical (probably olfactory) information. The possibility that visual or auditory stimuli influenced choice of channel in the maze was ruled out. Both males and females were strongly attracted to water taken from behind fish that were spawning and weakly attracted to the holding water of ripe fish that were not spawning. Brief speculation is offered about the role of chemical stimuli in the behavior of prespawning and spawning trout.

BKm minisatellite sequences are not sex associated but reveal DNA fingerprint polymorphisms in rainbow trout

Genome ◽  
1989 ◽  
Vol 32 (5) ◽  
pp. 865-868 ◽  
Author(s):  
Marilyn A. Lloyd ◽  
Mary J. Fields ◽  
Gary H. Thorgaard
Keyword(s):  
Rainbow Trout ◽  
Genomic Dna ◽  
Repetitive Sequences ◽  
Restriction Enzymes ◽  
Dna Fingerprint ◽  
Salmo Gairdneri ◽  
Agarose Gels ◽  
Outbred Strain ◽  
Males And Females ◽  
Female Snake

GATA-GACA repetitive sequences first isolated from a female snake (termed BKm sequences) and associated with sex chromosomes in some species were hybridized to DNA from rainbow trout (Salmo gairdneri). Genomic DNA was studied from three groups of rainbow trout: (i) randomly selected males and females from an outbred group, (ii) androgenetic individuals from an inbred strain, and (iii) parents and offspring of an outbred strain. Three restriction enzymes (EcoRI, HaeIII, or HinfI) were used to digest the genomic DNA. The DNA was electrophoresed in agarose gels, transferred to nylon membranes, and the GATA-GACA repetitive sequence probe was hybridized to this DNA. There was no evidence of sex-associated patterns of hybridization with the enzymes used. However, the sequences reveal DNA fingerprint polymorphisms which appear to be inherited in a stable manner.Key words: BKm, GATA-GACA repetitive sequences, DNA fingerprint, rainbow trout, Salmo gairdneri.

A General Polyploid Model for Analyzing Gene Segregation in Outcrossing Tetraploid Species

Genetics ◽  
2001 ◽  
Vol 159 (2) ◽  
pp. 869-882
Author(s):  
Rongling Wu ◽  
Maria Gallo-Meagher ◽  
Ramon C Littell ◽  
Zhao-Bang Zeng
Keyword(s):  
Molecular Markers ◽  
Chromosome Doubling ◽  
Plant Evolution ◽  
Likelihood Method ◽  
Double Reduction ◽  
Preferential Pairing ◽  
Higher Plant ◽  
Homologous Chromosomes ◽  
Gene Segregation ◽  
Homologous Chromosome Pairing

Abstract Polyploidy has played an important role in higher plant evolution and applied plant breeding. Polyploids are commonly categorized as allopolyploids resulting from the increase of chromosome number through hybridization and subsequent chromosome doubling or autopolyploids due to chromosome doubling of the same genome. Allopolyploids undergo bivalent pairing at meiosis because only homologous chromosomes pair. For autopolyploids, however, all homologous chromosomes can pair at the same time so that multivalents and, therefore, double reductions are formed. In this article, we use a maximum-likelihood method to develop a general polyploid model for estimating gene segregation patterns from molecular markers in a full-sib family derived from an arbitrary polyploid combining meiotic behaviors of both bivalent and multivalent pairings. Two meiotic parameters, one describing the preference of homologous chromosome pairing (expressed as the preferential pairing factor) typical of allopolyploids and the other specifying the degree of double reduction of autopolyploids, are estimated. The type of molecular markers used can be fully informative vs. partially informative or dominant vs. codominant. Simulation studies show that our polyploid model is well suited to estimate the preferential pairing factor and the frequency of double reduction at meiosis, which should help to characterize gene segregation in the progeny of autopolyploids. The implications of this model for linkage mapping, population genetic studies, and polyploid classification are discussed.

Inbreeding in Rainbow Trout (Salmo gairdneri)

1976 ◽  
Vol 33 (11) ◽  
pp. 2420-2426 ◽  
Author(s):  
Harold L. Kincaid
Keyword(s):  
Growth Rate ◽  
Rainbow Trout ◽  
Conversion Efficiency ◽  
Salmo Gairdneri ◽  
Feed Conversion ◽  
Feed Conversion Efficiency ◽  
Egg Hatchability ◽  
Inbreeding Coefficients ◽  
Two Generations ◽  
Sib Families

Effects of inbreeding on rainbow trout (Salmo gairdneri) were evaluated by a comparison of differences between inbred and outbred half-sib families reared as contemporaries during the 1st yr of life. Attention was focused on two levels of inbreeding expressed as inbreeding coefficients: F = 0.25, one generation of brother–sister matings, and F = 0.375, two generations of brother–sister matings. Although inbreeding at the F = 0.25 level in fall-spawning populations had no effect on egg hatchability, it significantly increased the frequency of crippled fry by 37.6% and significantly decreased feed conversion efficiency (5.6%), fry survival to 147 days (14.6%), and growth rate to 147 days (6%) and 364 days (23.2%). Effects of inbreeding at F = 0.375 were more pronounced; significant differences included increased frequency of crippled fry (191.5%) and decreased feed conversion efficiency (14.9%), fry survival to 147 days (29.7%), and growth rate to 147 day s (13.4%) and 364 days (33.5%). Application of the total effects of inbreeding on the number of fish remaining and the weight of fish remaining in a production lot at 1 yr of age indicated losses of 17.4 and 36.6% after one generation (F = 0.25) and 47.9 and 65.4% after two generations (F = 0.375) of brother–sister mating. Similar studies on a spring-spawning population produced similar results. General breeding methods that minimize the rate of inbreeding accumulation are discussed.

Temperature Selection of Rainbow Trout (Salmo gairdneri) Fingerlings in Vertical and Horizontal Gradients

1971 ◽  
Vol 28 (11) ◽  
pp. 1801-1804 ◽  
Author(s):  
R. W. McCauley ◽  
W. L. Pond
Keyword(s):  
Rainbow Trout ◽  
Salmo Gairdneri ◽  
Temperature Preference ◽  
Temperature Selection ◽  
Horizontal Gradients ◽  
Significant Difference ◽  
Preferred Temperatures ◽  
Laboratory Investigations ◽  
Horizontal Temperature Gradients ◽  
Selection Of

Preferred temperatures of underyearling rainbow trout (Salmo gairdneri) were determined in both vertical and horizontal temperature gradients. No statistically significant difference was found between the preferred temperatures by the two different methods. This suggests that the nature of the gradient plays a lesser role than generally believed in laboratory investigations of temperature preference.

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