Geographic variability and wing plasticity in Sitona sulcifrons (Coleoptera: Curculionidae)

1994 ◽  
Vol 84 (2) ◽  
pp. 269-273
Author(s):  
Tomáš Pavlíček
Keyword(s):  
Gene Flow ◽  
Phenotypic Plasticity ◽  
Genetic Variability ◽  
Relative Size ◽  
The Other ◽  
Wing Size ◽  
Geographic Variability ◽  
Polymorphic Loci ◽  
Local Populations ◽  
Total Variability

AbstractGenetic variability in four polymorphic loci and variation in phenotypic plasticity in relation to the relative size of wings, were compared and contrasted among eight local populations of Sitonasulcifrons Thunberg from the Czech and Slovak republics. The distances between localities from which samples were taken were between 49 and 492 kilometres. The results demonstrated that: 1. The variability between populations was 5.5% and the other 94.5% of the total variability was realized within populations. 2. Significant differences in allozyme frequencies among populations existed when distances were more than 100 km. A similar trend was also found in variability of relative wing size in males among populations when distances were more than 200 km. 3. Overall, a significant deficiency of heterozygotes in relation to Hardy-Weinberg predictions existed from all samples. The results support the idea that, at least inagricultural areas, gene flow in S. sulcifrons does not seem to be strong enough to stabilize one large interbreeding population in distances over 100 kilometres.

scholarly journals Genetic variability in four samples of Neoplecostomus yapo (Teleostei: Loricariidae) from the rio Paranapanema basin, Brazil

2009 ◽  
Vol 7 (1) ◽  
pp. 25-30 ◽  
Author(s):  
Juliana S. Philippsen ◽  
Erasmo Renesto ◽  
Ana Maria Gealh ◽  
Roberto F. Artoni ◽  
Oscar A. Shibatta ◽  
...  
Keyword(s):  
Genetic Variability ◽  
Genetic Distance ◽  
Corn Starch ◽  
The Other ◽  
Allozyme Electrophoresis ◽  
Polymorphic Loci ◽  
Two Samples ◽  
Starch Gel ◽  
The Mean ◽  
Electrophoresis Technique

Four samples of Neoplecostomus yapo were analyzed through the allozyme electrophoresis technique in corn starch gel. The allozyme pattern was similar to those found in N. paranensis with 24 loci scored. Two samples (ribeirão Atlântico and ribeirão Uraí) showed monomorphic bands for all 24 loci, whereas the other two (rio Verde and rio Fortaleza) showed 8.3% of polymorphic loci. The He genetic variability estimates for the rios Verde and Fortaleza populations were 0.0195 and 0.0179, respectively, too much inferior to the mean heterozygosity summed to species from the whole world (0.051). The Wright statistical values F IS = 0.5181, F IT = 0.5681 and F ST = 0.1039 and the genetic distance of Nei values showed that the four samples are genetically very similar to each other and that there is homozygote excess in the polymorphic loci.

scholarly journals ALLOZYME DIVERSITY IN CHESTNUT (CASTANEA SPP.).

HortScience ◽  
1994 ◽  
Vol 29 (7) ◽  
pp. 736a-736
Author(s):  
Hongwen Huang ◽  
Fenny Dane ◽  
Joseph Norton
Keyword(s):  
Genetic Variability ◽  
Genetic Distance ◽  
The Other ◽  
Changjiang River ◽  
Allozyme Diversity ◽  
Allele Distribution ◽  
Polymorphic Loci ◽  
The Changjiang River ◽  
Enzyme Systems ◽  
River Region

Allozyme genetic variability in three chestnut (Castanea) species was investigated using 19 loci from ten enzyme systems. G-tests of heterogeneity of isozymic allele distribution showed significant differences in both intraspecific and interspecific populations. C. mollissima was found to possess a significantly higher value of mean gene heterozygosity (H=0.3050±0.0419), percentage of polymorphic loci (P=84.21%) and average number of alleles per locus (A=2.05) than any other species in the Castanea section Eucustanon. When the genetic variability of populations of C. mollissimo from four regions in China was investigated, population from the Changjiang river region showed a markedly higher mean gene heterozygosity (H=0.3480±0.0436) than populations from the other regions. An approximately identical genetic distance between the population from the Changjiang river region and populations from three other regions was observed, while populations from the latter regions showed almost the same genetic distance from each other.

scholarly journals Drosophila suzukii wing spot size is robust to developmental temperature

2019 ◽  
Author(s):  
Ceferino Varón-González ◽  
Antoine Fraimout ◽  
Vincent Debat
Keyword(s):  
Sexual Selection ◽  
Phenotypic Plasticity ◽  
Relative Size ◽  
Spot Size ◽  
Invasion Success ◽  
Directional Asymmetry ◽  
Stabilizing Selection ◽  
Wing Size ◽  
Drosophila Suzukii ◽  
Developmental Temperature

ABSTRACTPhenotypic plasticity is an important mechanism allowing adaptation to new environments and as such it has been suggested to facilitate biological invasions. Under this assumption, invasive populations are predicted to exhibit stronger plastic responses than native populations. Drosophila suzukii is an invasive species whose males harbor a spot on the wing tip. In this study, by manipulating developmental temperature, we compare the phenotypic plasticity of wing spot size of two invasive populations with that of a native population. We then compare the results with data obtained from wild-caught flies from different natural populations. While both wing size and spot size are plastic to temperature, no difference in plasticity was detected between native and invasive populations, rejecting the hypothesis of a role of the wing-spot plasticity in the invasion success. In contrast we observed a remarkable stability in the spot-to-wing ratio across temperatures, as well as among geographic populations. This stability suggests either that the spot relative size is under stabilizing selection, or that its variation might be constrained by a tight developmental correlation between spot size and wing size. Our data show that this correlation was lost at high temperature, leading to an increased variation in the relative spot size, particularly marked in the two invasive populations. This suggests (i) that D. suzukii’s development is impaired by hot temperatures, in agreement with the cold-adapted status of this species; (ii) that the spot size can be decoupled from wing size, rejecting the hypothesis of an absolute constraint and suggesting that the wing color pattern might be under stabilizing (sexual) selection; (iii) that such sexual selection might be relaxed in the invasive populations. Finally, a subtle but consistent directional asymmetry in spot size was detected in favor of the right side in all populations and temperatures, possibly indicative of a lateralized sexual behavior.

Allozymic Variation and Species Diversity in North American Bosminidae

1994 ◽  
Vol 51 (4) ◽  
pp. 873-880 ◽  
Author(s):  
Rita De Melo ◽  
Paul D. N. Hebert
Keyword(s):  
Phenotypic Plasticity ◽  
Species Diversity ◽  
Genetic Variability ◽  
North American ◽  
Species Boundaries ◽  
Similar Species ◽  
Allozyme Analysis ◽  
Allozyme Data ◽  
Polymorphic Loci ◽  
Morphological Studies

North American members of the genus Bosmina show marked morphological variation and integradation, which have been attributed to the occurrence of both phenotypic plasticity and occasional hybridization between a small number of species. We employed allozyme analysis on 72 bosminid populations from 62 North American habitats to ascertain the validity of species boundaries and to verify the occurrence of hybridization. Results showed that levels of genetic variability (15.8% polymorphic loci, 10% individual heterozygosities) in bosminids were comparable with those reported in other zooplankton groups. Significant Hardy–Weinberg deviations were detected at 38% of polymorphic loci and were usually due to heterozygote deficiency. No clear evidence of interspecific hybridization was obtained, although some cases of heterozygote excess require further investigation. While prior morphological studies indicated the occurrence of only six species, the allozyme data revealed the presence of eight assemblages showing allelic substitutions at one or more loci. Each assemblage corresponded to a different species belonging to one of four subgenera (Bosmina, Eubosmina, Neobosmina, or Sinobosmina). Within two assemblages, individuals could be further partitioned into two morphologically distinct, but genetically similar species, leading to the recognition of 10 species in this study.

scholarly journals Assortative mating and the role of phenotypic plasticity in male competition: implications for gene flow among host-associated parasitoid populations

2008 ◽  
Vol 4 (5) ◽  
pp. 508-511 ◽  
Author(s):  
Lee M Henry
Keyword(s):  
Gene Flow ◽  
Phenotypic Plasticity ◽  
Local Adaptation ◽  
Assortative Mating ◽  
Host Species ◽  
Relative Size ◽  
Mating Preference ◽  
Adult Males ◽  
Mating Preferences

Local adaptation is promoted when habitat or mating preferences reduce gene flow between populations. However, gene flow is not only a function of dispersal but also of the success of migrants in their new habitat. In this study I investigated mating preference in conjunction with phenotypic plasticity using Aphidius parasitoids adapted to different host species. Males actively attempted to assortatively mate, but actual mating outcomes were strongly influenced by the relative size of the adult males. Results are discussed in the context of assortative mating in combination with the success of migrant males in mitigating gene flow between host-associated parasitoid populations.

Size Selectivity of Diamond and Square Mesh Codends in Pelagic Herring Trawls: Only Small Herring Will Notice the Difference

1992 ◽  
Vol 49 (10) ◽  
pp. 2104-2117 ◽  
Author(s):  
Petri Suuronen ◽  
Russell B. Millar
Keyword(s):  
Relative Size ◽  
Mesh Size ◽  
The Other ◽  
Size Selectivity ◽  
The Difference ◽  
Catch Rates ◽  
Two Sides ◽  
High Catch

A twin codend trawl was fished in the northern Baltic to study the size selectivity of square mesh and diamond mesh codends of 36-mm nominal mesh size. For each codend, 15 hauls were completed with a small mesh (20 mm) codend deployed on the other side of the trawl. The relative size of the catches in the two sides of the trawl varied considerably from haul to haul (the separator section was not operating properly) and selection curves were estimated from each individual haul using a method that incorporated the differences in catching efficiency of the two sides. The length of 50% retention decreased with increased catch for both the diamond and square mesh codends, although in neither case was this relationship statistically significant. Selection curves fitted to the combined haul data were asymmetric. The square mesh codend retained significantly less small herring than the diamond mesh codend, and for larger herring the two codends had similar selectivity. In both codends, most escapes occurred at the front of the catch bulge, from the upper side of the codend. At high catch rates, mesh blockage was observed for several metres ahead of the catch bulge during the later part of the tow.

scholarly journals Analysis of variance of partial diallel tables

2000 ◽  
Vol 23 (1) ◽  
pp. 229-234 ◽  
Author(s):  
José Marcelo Soriano Viana ◽  
Cosme Damião Cruz ◽  
Antonio Américo Cardoso ◽  
Adair José Regazzi
Keyword(s):  
Genetic Variability ◽  
Common Bean ◽  
Statistical Tests ◽  
Diallel Analysis ◽  
The Other ◽  
F1 Hybrids ◽  
Dominance Testing ◽  
The Common ◽  
The Mean ◽  
Partial Diallel

The theory of variance analysis of partial diallel tables, following Hayman's proposal of 1954, is presented. As several statistical tests yield similar inferences, the present analysis mainly proposes to assess genetic variability in two groups of parents and to study specific, varietal and mean heteroses. Testing the nullity of specific heteroses equals testing absence of dominance. Testing equality of varietal heteroses of the parents of a group is equivalent to testing the hypothesis that in the other group allelic genes have the same frequency. Rejection of the hypothesis that the mean heterosis is null indicates dominance. The information obtained complements that provided by diallel analysis involving parents and their F1 hybrids or F2 generations. An example with the common bean is included.

scholarly journals Comparison of Two Methods of Producing Adaptation of Saccade Size and Implications for the Site of Plasticity

1998 ◽  
Vol 79 (2) ◽  
pp. 704-715 ◽  
Author(s):  
Charles A. Scudder ◽  
Ekatherina Y. Batourina ◽  
George S. Tunder
Keyword(s):  
Relative Size ◽  
Neural Mechanisms ◽  
The Other ◽  
Rapid Adaptation ◽  
Adaptive Mechanisms ◽  
Saccade Size ◽  
Orbital Position ◽  
One Step ◽  
Induced Changes ◽  
Visual Error

Scudder, Charles A., Ekatherina Y. Batourina, and George S. Tunder. Comparison of two methods of producing adaptation of saccade size and implications for the site of plasticity. J. Neurophysiol. 79: 704–715, 1998. Saccade accuracy is known to be maintained by adaptive mechanisms that progressively reduce any visual error that consistently exists at the end of saccades. Experimentally, the visual error is induced using one of two paradigms. In the first, the horizontal and medial recti of trained monkeys are tenectomized and allowed to reattach so that both muscles are paretic. After patching the unoperated eye and forcing the monkey to use the “paretic eye,” saccades initially undershoot the intended target, but gradually increase in size until they almost acquire the target in one step. In the second, the target of a saccade is displaced in midsaccade so that the saccade cannot land on target. Again saccade size adapts until the target can be acquired in one step. Because adaptation with the latter paradigm is very rapid but adaptation using the former is slow, it has frequently been questioned whether or not the two forms of adaptation depend on the same neural mechanisms. We show that the rate of adaptation in both paradigms depends on the number of possible visual targets, so that when this variable is equated, adaptation occurs at similar rates in both paradigms. To demonstrate further similarities between the result of the two paradigms, an experiment using intrasaccadic displacements was conducted to show that rapid adaptation possesses the capacity to produce gain changes that vary with orbital position. The relative size of intrasaccadic displacements were graded with orbital position so as to mimic the position-dependent dysmetria initially produced by a single paretic extraocular muscle. Induced changes in saccade size paralleled the size of the displacements, being largest for saccades into one hemifield and being negligible for saccades into the other hemifield or in the opposite direction. Collectively, the data remove the rational for asserting that adaptation produced by the two paradigms depends on separate neural mechanisms. We argue that adaptation produced by both paradigms depends on the cerebellum.

scholarly journals The use of random amplified polymorphic DNA to evaluate the genetic variability of Ponkan mandarin (Citrus reticulata Blanco) accessions

2000 ◽  
Vol 23 (1) ◽  
pp. 169-172 ◽  
Author(s):  
Helvécio Della Coletta Filho ◽  
Marcos Antonio Machado ◽  
M. Luiza P.N. Targon ◽  
Jorgino Pompeu Jr.
Keyword(s):  
Genetic Variability ◽  
Rapd Analysis ◽  
Random Amplified Polymorphic Dna ◽  
Point Mutations ◽  
The Other ◽  
Citrus Reticulata ◽  
Random Primers ◽  
Citrus Reticulata Blanco ◽  
Ponkan Mandarin

RAPD analysis of 19 Ponkan mandarin accessions was performed using 25 random primers. Of 112 amplification products selected, only 32 were polymorphic across five accessions. The absence of genetic variability among the other 14 accessions suggested that they were either clonal propagations with different local names, or that they had undetectable genetic variability, such as point mutations which cannot be detected by RAPD.

scholarly journals Genetic structure and gene flow of Eugenia dysenterica natural populations

2005 ◽  
Vol 40 (10) ◽  
pp. 975-980 ◽  
Author(s):  
Maria Imaculada Zucchi ◽  
José Baldin Pinheiro ◽  
Lázaro José Chaves ◽  
Alexandre Siqueira Guedes Coelho ◽  
Mansuêmia Alves Couto ◽  
...  
Keyword(s):  
Gene Flow ◽  
Genetic Variability ◽  
Pearson Correlation ◽  
Natural Populations ◽  
Similarity Index ◽  
Genetic Distances ◽  
Strong Positive Correlation ◽  
Randomly Amplified Polymorphic Dna ◽  
Jaccard Similarity ◽  
Eugenia Dysenterica

This study was carried out to assess the genetic variability of ten "cagaita" tree (Eugenia dysenterica) populations in Southeastern Goiás. Fifty-four randomly amplified polymorphic DNA (RAPD) loci were used to characterize the population genetic variability, using the analysis of molecular variance (AMOVA). A phiST value of 0.2703 was obtained, showing that 27.03% and 72.97% of the genetic variability is present among and within populations, respectively. The Pearson correlation coefficient (r) among the genetic distances matrix (1 - Jaccard similarity index) and the geographic distances were estimated, and a strong positive correlation was detected. Results suggest that these populations are differentiating through a stochastic process, with restricted and geographic distribution dependent gene flow.

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