Allozyme and microsatellite diversity in natural and domestic populations of turbot (Scophthalmus maximus) in comparison with other Pleuronectiformes

2002 ◽  
Vol 59 (9) ◽  
pp. 1460-1473 ◽  
Author(s):  
C Bouza ◽  
P Presa ◽  
J Castro ◽  
L Sánchez ◽  
P Martínez
Keyword(s):  
Genetic Diversity ◽  
Natural Populations ◽  
Scophthalmus Maximus ◽  
Local Scale ◽  
Mutation Rates ◽  
Microsatellite Data ◽  
Allozyme Diversity ◽  
Historical Bottlenecks ◽  
Turbot Scophthalmus Maximus ◽  
Allozyme Loci

Twelve microsatellite and 28 allozyme loci were employed to analyse genetic diversity in natural and domestic populations of turbot (Scophthalmus maximus) from northwest Spain in comparison with other flatfish species with similar habitat, life history, and geographic distribution—the brill (Scophthalmus rhombus) and the flounder (Platichthys flesus). These species had shown much higher allozyme diversity than turbot in previous studies, and were used as a reference to check for putative historical bottlenecks in turbot. Significantly lower genetic variability in turbot than in brill and flounder was confirmed with allozymes, but not with the highly variable microsatellite loci. This intermarker discrepancy could be explained by different mutation rates in relation with historical bottlenecks along turbot evolution. A significantly lower genetic diversity was observed in a domestic strain of turbot than in natural populations of this species. This sample evidenced a strong family structure from microsatellite data, which suggests caution against the use of commercial batches for broodstock foundation in turbot farming. A strong concordance was found across the two categories of markers used when analysing the pattern of genetic subdivision at a local scale within the three species analysed, low and nonsignificant genetic differentiation being observed between Atlantic and Cantabric areas.

scholarly journals Conservation aspects of natural populations and captive-bred stocks of turbot (Scophthalmus maximus) and Dover sole (Solea solea) using estimates of genetic diversity

2007 ◽  
Vol 64 (6) ◽  
pp. 1173-1181 ◽  
Author(s):  
Athanasios Exadactylos ◽  
Mark J. Rigby ◽  
Audrey J. Geffen ◽  
John P. Thorpe
Keyword(s):  
Genetic Diversity ◽  
Population Structure ◽  
Natural Populations ◽  
Genetic Data ◽  
Scophthalmus Maximus ◽  
Effective Population ◽  
Solea Solea ◽  
Population Sizes ◽  
Turbot Scophthalmus Maximus ◽  
Dover Sole

Exadactylos, A., Rigby, M. J., Geffen, A. J., and Thorpe, J. P. 2007. Conservation aspects of natural populations and captive-bred stocks of turbot (Scophthalmus maximus) and Dover sole (Solea solea) using estimates of genetic diversity. – ICES Journal of marine Science, 64: 1173–1181. Population genetic analyses have been highly successful in predicting inter- and intraspecific evolutionary relationships, levels of gene flow, genetic divergence, and effective population sizes. Parameters estimated are evolutionary averages and are therefore relevant for addressing contemporary ecological or conservation issues. Changes in genetic variation within the range of a species may indicate patterns of population structure resulting from past ecological and demographic events that are otherwise difficult to infer, so may provide an insight into evolutionary development. Genetic data, drawn from 14 enzyme loci amplified from two populations of turbot (Scophthalmus maximus) and five populations of Dover sole (Solea solea) from the Irish Sea were used to examine population structure estimated from measures of genetic diversity. The aim was to provide an empirical assessment of whether artificial propagation poses a genetic threat to conservation of naturally spawning populations, and whether the fitness for natural spawning and rearing can be rapidly and substantially reduced or increased by artificial propagation. Because of prolonged overfishing, turbot and sole populations in the region are below natural levels, and survive in small local populations in fragmented habitats. Genetic data derived from allozymes have shown that populations are characterized by relatively low levels of genetic diversity. A hypothetical model supporting genetic population substructure, such as range expansion with founder-flush effects, and subsequent population decline with small effective population sizes was considered. Observations support our belief that conservation measures based on genetic diversity have to be developed to ensure the survival of this diverse gene pool.

scholarly journals Historical bottlenecks decrease genetic diversity in natural populations of Dryopteris cristata

Heredity ◽  
2001 ◽  
Vol 87 (3) ◽  
pp. 344-355 ◽  
Author(s):  
Urs Landergott ◽  
Rolf Holderegger ◽  
Gregor Kozlowski ◽  
J Jakob Schneller
Keyword(s):  
Genetic Diversity ◽  
Natural Populations ◽  
Historical Bottlenecks

Low genetic diversity at allozyme loci in Juglans cinerea

2000 ◽  
Vol 78 (9) ◽  
pp. 1238-1243 ◽  
Author(s):  
Ricardo Morin ◽  
Jean Beaulieu ◽  
Marie Deslauriers ◽  
Gaëtan Daoust ◽  
Jean Bousquet
Keyword(s):  
Genetic Diversity ◽  
Population Structure ◽  
Deciduous Forest ◽  
Polymorphic Locus ◽  
Natural Populations ◽  
Minor Component ◽  
Temperate Deciduous Forest ◽  
Juglans Cinerea ◽  
Low Genetic Diversity ◽  
Allozyme Loci

Butternut (Juglans cinerea L.) is a minor component of the temperate deciduous forest region of northeastern North America, but it is severely affected by the butternut canker (Sirococcus clavigignenti-juglandacearum Nair, Kostichka, and Kuntz) in the southern part of its natural range. Genetic diversity and population structure in as-yet unaffected or only slightly affected natural populations were evaluated at 12 isozyme loci. The genetic diversity estimates were low with values much below those estimated in other species of the same genus or in boreal tree species, with 25 and 13.9% polymorphic loci at the species and population levels, respectively; 1.3 and 2.3 alleles per locus and per polymorphic locus, respectively, at the species level; and an average observed heterozygosity of 0.028. Population differentiation was low, with the exception of one unique population. The implications for advanced conservation are discussed.Key words: butternut, isozymes, Sirococcus, canker, population structure.

Evolutionary Processes and Theory: The Ecological-Genetics Interface

1993 ◽  
Vol 27 (7-8) ◽  
pp. 489-496 ◽  
Author(s):  
Eviatar Nevo
Keyword(s):  
Genetic Diversity ◽  
Life Histories ◽  
Natural Populations ◽  
Evolutionary Process ◽  
Ecological Factors ◽  
Ecological Genetics ◽  
Dna Polymorphisms ◽  
Starch Gel Electrophoresis ◽  
Biological Variables ◽  
Allozyme Loci

The evolutionary process is reviewed in terms of the ecological-genetics interface based on genetic diversity in natural populations of plants and animals, using the environmental-genetic correlation methodology at three geographic levels: (1) Local, several species in Israeli microsites; (2) Regional, 21 species across Israel and 2 species in the Near East; and (3) Global, 1111; 184 and 189 species in three studies across the planet. The species analyzed are taxonomically unrelated, and vary in their ecologies, demographies, life histories, and other biological variables. They were mostly tested by horizontal starch gel electrophoresis for allozymic diversity, averaging 25 gene loci, and other genetic polymorphisms. In addition, ten studies involved DNA polymorphisms. The following results were found at all three geographic levels: (1) The levels of genetic diversity vary nonrandomly and are structured within and among populations, species, and higher taxa; and (2) Genetic diversity is correlated with niche width, and partly predictable, primarily by ecological factors. These results corroborate the adaptive, environmental theory of genetic diversity. They were also verified for several allozyme loci in controlled laboratory experiments in pollution biology. Natural selection in its various forms appears to be a major force maintaining, differentiating and orienting evolutionary change in protein and DNA polymorphisms.

The genetic structure and the conservation of the five natural populations of Pinusradiata

1988 ◽  
Vol 18 (5) ◽  
pp. 506-514 ◽  
Author(s):  
G. F. Moran ◽  
J. C. Bell ◽  
K.G. Eldridge
Keyword(s):  
Genetic Diversity ◽  
Natural Populations ◽  
Allozyme Variation ◽  
Conservation Strategies ◽  
Mainland Population ◽  
Island Populations ◽  
Expected Heterozygosity ◽  
Environmental Criteria ◽  
Total Genetic Diversity ◽  
Allozyme Loci

Pinusradiata is restricted to three mainland coastal populations in California and two island populations off Baja California, Mexico. In this study each population was divided into two geographic stands based on natural disjunctions within populations. In addition to the division mentioned above, each mainland population was also divided into a number of ecological stands based on ecological and environmental criteria. Genetic variation was measured by analysing 31 allozyme loci electrophoretically using germinated seed from 272 families across all stands and populations. Moderate levels of allozyme variation were found as shown by population averages for mean number of alleles per locus (1.79), percent polymorphic loci (46.4%, 0.99 criterion), and expected heterozygosity (0.098). In fact, the overall genetic diversity in P. radiata (HT = 0.117) is low compared with that of other conifers. In comparison with populations, the levels of allozyme variation in both ecological and geographic stands were slightly lower (means across ecological stands: A = 1.56, P = 39.3%, and He = 0.095). Of the total genetic diversity in P. radiata, 16.2% could be apportioned between populations, a high proportion for a conifer. In contrast, only 2.0 and 1.3% of the genetic diversity on average within mainland populations was between ecological and geographic stands, respectively. These results indicate a low level of genetic differentiation within populations, at least based on the ecological or geographic criteria used in this study. The implications and usefulness of these findings for the development of insitu conservation strategies are discussed.

scholarly journals Diversity and genetic structure in natural populations of Hancornia speciosa var. speciosa Gomes in northeastern Brazil

2012 ◽  
Vol 34 (4) ◽  
pp. 1143-1153 ◽  
Author(s):  
Georgia Vilela Martins ◽  
Luiza Suely Semen Martins ◽  
Elizabeth Ann Veasey ◽  
Ildo Eliezer Lederman ◽  
Edson Ferreira da Silva
Keyword(s):  
Genetic Diversity ◽  
Genetic Structure ◽  
Genetic Variability ◽  
Natural Populations ◽  
Genetic Erosion ◽  
Northeastern Brazil ◽  
Natural Occurrence ◽  
Spatial Pattern Analysis ◽  
Hancornia Speciosa ◽  
Allozyme Loci

Hancornia speciosa Gomes is a fruit tree native from Brazil that belongs to Apocinaceae family, and is popularly known as Mangabeira. Its fruits are widely consumed raw or processed as fruit jam, juices and ice creams, which have made it a target of intense exploitation. The extractive activities and intense human activity on the environment of natural occurrence of H. speciosa has caused genetic erosion in the species and little is known about the ecology or genetic structure of natural populations. The objective of this research was the evaluation of the genetic diversity and genetic structure of H. speciosa var. speciosa. The genetic variability was assessed using 11 allozyme loci with a sample of 164 individuals distributed in six natural populations located in the States of Pernambuco and Alagoas, Northeastern Brazil. The results showed a high level of genetic diversity within the species (<img border=0 id="_x0000_i1026" src="/img/revistas/rbf/v34n4/a23img01.jpg" align=absmiddle>e= 0.36) seeing that the most of the genetic variability of H. speciosa var. speciosa is within its natural populations with low difference among populations ( <img border=0 id="_x0000_i1027" src="/img/revistas/rbf/v34n4/a23img02.jpg" align=absmiddle > or = 0.081). The inbreeding values within (<img border=0 id="_x0000_i1028" src="/img/revistas/rbf/v34n4/a23img03.jpg" align=absmiddle> = -0.555) and among populations (<img border=0 id="_x0000_i1029" src="/img/revistas/rbf/v34n4/a23img04.jpg" align=absmiddle> =-0.428) were low showing lacking of endogamy and a surplus of heterozygotes. The estimated gene flow ( <img border=0 id="_x0000_i1030" src="/img/revistas/rbf/v34n4/a23img05.jpg" align=absmiddle>m ) was high, ranging from 2.20 to 13.18, indicating to be enough to prevent the effects of genetic drift and genetic differentiation among populations. The multivariate analyses indicated that there is a relationship between genetic and geographical distances, which was confirmed by a spatial pattern analysis using Mantel test (r = 0.3598; p = 0.0920) with 1000 random permutations. The high genetic diversity index in these populations indicates potential for in situ genetic conservation.

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