Decrease of the Effective Population Size during Maintenance of the Guppy Strain

Fujio, Yoshihisa; Nakajima, Masamichi; Barinova, Anna Alexandrovna

doi:10.2331/fishsci.65.362

Cited by 10 publications

(3 citation statements)

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“…In the present study, allozyme and microsatellite analysis of three naturalized populations and nine domestic strains revealed that genetic variation measured by mean heterozygosity was significantly lower in the domestic strains than in the naturalized populations. As reported in other fish species (Allendorf & Phelps, 1980;Ryman & Ståhl, 1980;Taniguchi et al, 1983;Agnèse et al, 1995), the domestic guppy strains may lose their genetic variation due to bottlenecks at their foundation and through subsequent low effective population sizes (Barinova et al, 1998;Fujio et al, 1999). This is also supported by the previous allozyme data that demonstrates significant decreases in the mean heterozygosity in the domestic guppy strains during 10 years of maintenance, or c. 20-30 generations (Barinova et al, 1997b).…”

Section: Discussionsupporting

confidence: 72%

Heterosis for neonatal survival in the guppy

Shikano

2002

Journal of Fish Biology

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Neonatal survival rate ranged from 91·8 to 100·0% in 12 populations of the guppy Poecilia reticulata, and was higher in naturalized Japanese stream populations than in domestic strains. Mean heterozygosity at five allozyme and four microsatellite loci varied between 0·112 and 0·430 and was significantly correlated with neonatal survival rate among populations, suggesting that inbreeding decreases neonatal survival. Diallel and reciprocal crosses among four domestic strains demonstrated heterosis for neonatal survival. These results indicate that neonatal survival is genetically affected by heterosis and its antithesis, inbreeding depression. The relationship between neonatal survival and the mean heterozygosity suggests that overall heterozygosity is important for neonatal survival of the guppy. 2002 The Fisheries Society of the British Isles

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Section: Discussionsupporting

confidence: 72%

Heterosis for neonatal survival in the guppy

Shikano

2002

Journal of Fish Biology

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“…It would occur initially because of a founder effect, the situation in which small numbers of brooders were taken from the natural population for domestication (Allendorf andPhelps 1980, Norris et al 1999). The populations keep facing allele loss during domestication process due to inbreeding and or genetic drift (Fujio et al 1999). The effect of allele loss have been clearly demonstrated in hatchery populations of fi sh and shellfi sh; for example, Atlantic salmon, Salmo salar (Koljenon et al 2002);…”

Section: Resultsmentioning

confidence: 99%

Allozyme Based Genetic Variation between Hatchery and Natural Populations of Sahar (Tor putitora)

Wagle¹,

Pradhan²,

Gurung³

et al. 2015

J. Nat. Hist. Mus.

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Sahar (Tor putitora) formed a substantial natural fi shery in the major riverine and lacustrine ecosystem of Nepal. Biological diversity of this species is being threatened by various anthropogenic activities. In view of the conservational value and the aquaculture potential of T. putitora, signifi cant development in artifi cial propagation of this species has been achieved. The successful hatchery production of T. putitora brought to the forefront problematic questions regarding genetic variation of the hatchery stocks. A study was, therefore, conducted to determine the genetic variability within and between hatchery stocks and their wild counterparts of T. putitora using allozyme markers.Analyses of seven enzyme systems resuled in 11 loci being resolved from lake population and two consecutive generations of hatchery populations of T. putitora. Based on fi ve polymorphic loci, all populations had percentage polymorphic loci 45.45. Signifi cant reduction (P<0.01) in number of alleles per locus was evident in hatchery populations (1.45 ±0.181) compared to lake population (1.72 ±0.90). Loss of rear alleles, EST-2*74, IDH*70 and GDH*33 occurred in both of the hatchery populations which were present in wild counterparts-the lake population. All populations under study conform to the Hardy-Weinberg equilibrium at the 1% level. Although not signifi cant (P>0.05), observed heterozygosity increased in fi rst generation of hatchery population (H o = 0.181 ±0.233) compared to natural population (H o =0.179±0.221). The H o of second generation of hatchery population was lowest (0.119 ±0.143) among the populations studied. Loss of rare alleles from the two generations of hatchery population, while these alleles were present in corresponding natural populations suggested the founders (20-30 individuals) of the hatchery populations probably represented bottlenecks to very small effective population size (N e ).

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“…Hence F cbased estimators of N e remain frequently used in pracfrequencies were simulated and F c was computed. All simulations were carried out using Mathematica (Woltice (Fujiio et al 1999;Turner et al 1999;Goldringer et al 2001;Shikano et al 2001). Properties of F c -based fram 1996).…”

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confidence: 99%

On the Distribution of Temporal Variations in Allele Frequency

Goldringer

Bataillon

2004

Genetics

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The effective population size (N e ) is frequently estimated using temporal changes in allele frequencies at neutral markers. Such temporal changes in allele frequencies are usually estimated from the standardized variance in allele frequencies (F c ). We simulate Wright-Fisher populations to generate expected distributions of F c and of F c (F c averaged over several loci). We explore the adjustment of these simulated F c distributions to a chi-square distribution and evaluate the resulting precision on the estimation of N e for various scenarios. Next, we outline a procedure to test for the homogeneity of the individual F c across loci and identify markers exhibiting extreme F c -values compared to the rest of the genome. Such loci are likely to be in genomic areas undergoing selection, driving F c to values greater (or smaller) than expected under drift alone. Our procedure assigns a P-value to each locus under the null hypothesis (drift is homogeneous throughout the genome) and simultaneously controls the rate of false positive among loci declared as departing significantly from the null. The procedure is illustrated using two published data sets: (i) an experimental wheat population subject to natural selection and (ii) a maize population undergoing recurrent selection.T HE effective population size (N e ), defined as the 1/2N e ) t ] (Crow and Kimura 1970). If t is not too large (t Ӷ N e ), N e can be approximated by N e Ϸ (P 0 (1 Ϫ P 0 )t)/ size of an ideal Wright-Fisher population undergoing the same rate of genetic change as the population (2V(P t )) and therefore an estimator for N e based on the standardized variance in allele frequency is (V(P t ))/ under study, is an essential parameter to predict the evolution of a population due to genetic drift in terms of (P 0 (1 Ϫ P 0 )). Nei and Tajima (1981) proposed estimating the standardized variance in allele frequency between rates of loss of genetic variation, fixation of deleterious alleles, or inbreeding (Wright 1969). However, obgeneration t x and t y for each locus l with K l alleles as taining direct estimates of N e from demographic data has often proved difficult. An alternative is to use indi-rect methods, for instance, those based on the measurement of temporal changes in allele frequencies at neuwhere p x(i,l) [respectively p y(i,l) ] represents the frequency tral markers (Krimbas and Tsakas 1971; Waples of allele i at locus l in the sample of S x individuals drawn 1989a). The foundation of these methods is that the at generation t x (respectively S y individuals at t y ). A variance of allele frequency due to drift from parents weighted mean of F c,l -values across several loci, to offspring, V(P 1 ), depends on N e as follows: V(P 1 ) ϭ P 0 (1 Ϫ P 0 )/2N e , where P 0 is the frequency in the parentalpopulation. After t generations of drift, the expected frequency of the allele is E(P t ) ϭ P 0 and the variance is then typically used to estimate N e via of the allele frequency, V(P t ) ϭ E(P t Ϫ P 0 ) 2 , can be written as a functi...

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Decrease of the Effective Population Size during Maintenance of the Guppy Strain

Cited by 10 publications

References 4 publications

Heterosis for neonatal survival in the guppy

Heterosis for neonatal survival in the guppy

Allozyme Based Genetic Variation between Hatchery and Natural Populations of Sahar (Tor putitora)

On the Distribution of Temporal Variations in Allele Frequency

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