scholarly journals Enzymatic analysis in Anopheles nuneztovari Gabaldón (Diptera, Culicidae)

2000 ◽  
Vol 60 (4) ◽  
pp. 539-550 ◽  
Author(s):  
V. M. SCARPASSA ◽  
W. P. TADEI
Keyword(s):  
Genetic Variation ◽  
Genetic Variability ◽  
Genetic Divergence ◽  
Allelic Variation ◽  
Natural Populations ◽  
Brazilian Amazon ◽  
High Variability ◽  
The Other ◽  
Enzymatic Analysis ◽  
Phenotypic Variations

Enzymatic analysis in Anopheles nuneztovari was made using four populations from the Brazilian Amazon and two from Colombia. The enzymes ME and XDH presented a monomorphic locus in all of the studied populations. EST and LAP presented a higher number of loci. In EST, genetic variation was observed in the five loci; LAP presented four loci, with allec variation in two loci. In IDH, three activity regions were stained, with genetic variation for locus Idh-1 in the Brazilian Amazon populations. A locus for MDH was observed, with genetic variation in the six populations. A region was verified for ACON, with four alleles in Sitronela and three in the other populations. PGM constituted one locus, with a high variability in the Brazilian Amazon populations. A locus was observed for 6-PGD with allelic variation in all of the populations with the exception of Tibú. Enzyme PGI presented two loci, both with genetic variability in the Tucuruí population. The enzyme alpha-GPD showed an activity region with polymorphism in the Tucuruí, Tibú and Sitronela populations. The phenotypic variations detected for these enzymes suggest that four (EST, LAP, ACON and PGM) possess monomeric structures and five (IDH, MDH, 6-PGD, PGI and alpha-GPD) dimeric structures in their proteins. These enzymes constitute in important markers to estimate variability and genetic divergence in natural populations of A. nuneztovari.

scholarly journals The molecular through ecological genetics of abnormal abdomen. IV. Components of genetic variation in a natural population of Drosophila mercatorum.

Genetics ◽  
1992 ◽  
Vol 130 (2) ◽  
pp. 355-366
Author(s):  
H Hollocher ◽  
A R Templeton ◽  
R DeSalle ◽  
J S Johnston
Keyword(s):  
Genetic Variation ◽  
Natural Population ◽  
Allelic Variation ◽  
Natural Populations ◽  
Developmental Time ◽  
Ecological Genetics ◽  
Adult Longevity ◽  
Genetic Determinants ◽  
Drosophila Mercatorum ◽  
Y Chromosomes

Abstract Natural populations of Drosophila mercatorum are polymorphic for a phenotypic syndrome known as abnormal abdomen (aa). This syndrome is characterized by a slow-down in egg-to-adult developmental time, retention of juvenile abdominal cuticle in the adult, increased early female fecundity, and decreased adult longevity. Previous studies revealed that the expression of this syndrome in females is controlled by two closely linked X chromosomal elements: the occurrence of an R1 insert in a third or more of the X-linked 28S ribosomal genes (rDNA), and the failure of replicative selection favoring uninserted 28S genes in larval polytene tissues. The expression of this syndrome in males in a laboratory stock was associated with the deletion of the rDNA normally found on the Y chromosome. In this paper we quantify the levels of genetic variation for these three components in a natural population of Drosophila mercatorum found near Kamuela, Hawaii. Extensive variation is found in the natural population for both of the X-linked components. Moreover, there is a significant association between variation in the proportion of R1 inserted 28S genes with allelic variation at the underreplication (ur) locus such that both of the necessary components for aa expression in females tend to cosegregate in the natural population. Accordingly, these two closely linked X chromosomal elements are behaving as a supergene in the natural population. Because of this association, we do not believe the R1 insert to be actively transposing to an appreciable extent. The Y chromosomes extracted from nature are also polymorphic, with 16% of the Ys lacking the Y-specific rDNA marker. The absence of this marker is significantly associated with the expression of aa in males. Hence, all three of the major genetic determinants of the abnormal abdomen syndrome are polymorphic in this natural population.

scholarly journals Enzyme variability in the Drosophila willistoni Group. V. Genic variation in natural populations of Drosophila equinoxialis

1972 ◽  
Vol 20 (1) ◽  
pp. 19-42 ◽  
Author(s):  
Francisco J. Ayala ◽  
Jeffrey R. Powell ◽  
Martin L. Tracey
Keyword(s):  
Genetic Variation ◽  
Allelic Variation ◽  
Natural Populations ◽  
Starch Gel Electrophoresis ◽  
Gene Frequencies ◽  
Group V ◽  
Neutral Genetic Variation ◽  
Starch Gel ◽  
Genic Variation ◽  
Standard Techniques

SUMMARYWe have studied genetic variation at 27 loci in 42 samples from natural populations of a neotropical species, Drosophila equinoxialis, using standard techniques of starch-gel electrophoresis to detect allelic variation in genes coding for enzymes. There is considerarle genetic variability in D. equinoxialis. We have found allelic variation in each of the 27 loci, although not in every population. On the average, 71% of the loci are polymorphic – that is, the most common allele has a frequency no greater than 0·95 – in a given population. An individual is heterozygous on the average at 21·8% of its loci.The amount of genetic variation fluctuates widely from locus to locus. At the Mdh-2 locus arout 1% of the individuals are heterozygotes; at the other extreme more than 56% of the individuals are heterozygous at the Est-3. At any given locus the configuration of allelic frequencies is strikingly similar from locality to locality. At each and every locus the same allele is generally the most common throughout the distribution of the species. Yet differences in gene frequencies occur between localities. The pattern of genetic variation is incompatible with the hypothesis that the variation is adaptively neutral. Genetic variation in D. equinoxialis is maintained by balancing natural selection.The amount and pattern of genetic variation is similar in D. equinoxialis and its sibling species, D. willistoni. Yet the two species are genetically very different. Different sets of alleles occur at nearly 40% of the loci.

scholarly journals Genetic divergence among soybean cultivars in irrigated lowland in the State of Tocantins

2012 ◽  
Vol 42 (3) ◽  
pp. 395-400 ◽  
Author(s):  
Joênes Mucci Peluzio ◽  
Luiz Paulo Miranda Pires ◽  
Leandro Lopes Cancellier ◽  
Flávio Sérgio Afférri ◽  
Gustavo André Colombo ◽  
...  
Keyword(s):  
Experimental Design ◽  
Genetic Variability ◽  
Genetic Divergence ◽  
Nearest Neighbor ◽  
Optimization Method ◽  
High Variability ◽  
Soybean Cultivars ◽  
Days To Maturity ◽  
Multivariate Procedures ◽  
Genetic Dissimilarity

In order to evaluate the genetic divergence among soybean cultivars, an assay was carried out at Formoso do Araguaia, TO, Brazil, in off-season of 2007, in irrigated lowland conditions. The experimental design were randomized blocks with 12 treatments and three replications. Genetic divergence was evaluated by multivariate procedures: Mahalanobis distance, Tocher clustering method's and nearest neighbor method. It was observed the formation of two distinct groups by the dendrogram of genetic dissimilarity, which were identical to those groups formed by Tocher's method. The Tocher optimization method and the nearest neighbor agreed among themselves. The traits number of days to maturity, plant height and weight of 100 seed were the ones that most contributed for genetic dissimilarity. The presence of genetic variability allowed the identification of dissimilar cultivars with high average for the evaluated traits. The hybridations 'DOKO' x 'CONQUEST' and 'DOKO' x 'FT-2000' are promising to obtain segregating populations with high variability

Genetic Variability for Herbicide Reaction in Plant Populations

Weed Science ◽  
1983 ◽  
Vol 31 (5) ◽  
pp. 652-657 ◽  
Author(s):  
Steven C. Price ◽  
James E. Hill ◽  
R. W. Allard
Keyword(s):  
Genetic Variation ◽  
Genetic Variability ◽  
Analysis Of Variance ◽  
Genetic Variance ◽  
Natural Populations ◽  
Herbicide Tolerance ◽  
Avena Fatua ◽  
Wild Oat ◽  
Plant Populations ◽  
Avena Barbata

The level of genetic variation for tolerance to herbicides was quantified in populations of slender wild oat (Avena barbata Brott. # AVEBA), wild oat (Avena fatua L. # AVEFA), and godetia (Clarkia williamsonii Lewis & Lewis) that had not been previously exposed to herbicides. Seedlings of wild oat and godetia were treated with barban (4-chloro-2-butynl-m-chlorocarbanilate) and bromoxynil (3,5-dibromo-4-hydroxybenzonitrile), respectively. The plants were rated for phytotoxic effects following treatment. A one-way analysis of variance on arcsin-transformed phytotoxicity ratings showed significant amounts of inter- and intrapopulation variability for herbicide reaction. Furthermore, the amount of genetic variance for herbicide reaction is higher than expected on the basis of mutation alone, suggesting selection favoring genes conferring herbicide tolerance occurs in natural populations.

scholarly journals Genetic variation, phylogenetic relationship and spatial distribution of ‘Candidatus Phytoplasma ulmi’ strains in Germany

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
B. Schneider ◽  
B. Hüttel ◽  
C. Zübert ◽  
M. Kube
Keyword(s):  
Phylogenetic Analysis ◽  
Genetic Variation ◽  
Spatial Distribution ◽  
Genetic Variability ◽  
Distribution Pattern ◽  
Phylogenetic Relationship ◽  
Regional Distribution ◽  
The Other ◽  
Flavescence Dorée ◽  
Regional Distribution Pattern

AbstractA recent survey in Germany revealed the wide presence of ‘Candidatus Phytoplasma ulmi’ in native elm stands. Accessions were studied for their genetic variability and phylogenetic relationship based on the conserved groEL and the variable imp gene. While the groEL sequences revealed a high intraspecific homology of more than 99%, the homology of the imp gene dropped to 71% between distantly related sequences. Twenty-nine groEL and 74 imp genotypes were distinguished based on polymorphic sites. Phylogenetic analysis of the groEL gene clustered all ‘Ca. P. ulmi’ strains and separated them from related phytoplasmas of the 16SrV group. The inferred phylogeny of the imp gene resulted in a different tree topology and separated the ‘Ca. P. ulmi’ genotypes into two clusters, one closely related to the flavescence dorée phytoplasma strain FD-D (16SrV-D), the other affiliated with the flavescence dorée phytoplasma strains FD-C and FD70 and the alder yellows phytoplasma (16SrV-C). In both phylograms, ‘Ca. P. ulmi’ genotypes from Scots elm trees formed a coherent cluster, while genotypes from European white elms and field elms grouped less strictly. The regional distribution pattern was congruent for some of the groEL and imp genotypes, but a strict linkage for all genotypes was not apparent.

scholarly journals GENETIC CHANGE AND RATES OF CLADOGENESIS

Genetics ◽  
1975 ◽  
Vol 81 (4) ◽  
pp. 757-773
Author(s):  
John C Avise ◽  
Francisco J Ayala
Keyword(s):  
Genetic Differentiation ◽  
Genetic Distance ◽  
Genetic Divergence ◽  
Natural Populations ◽  
Genetic Distances ◽  
Genetic Change ◽  
The Other ◽  
Limited Information ◽  
History Of ◽  
The Relationship

ABSTRACT Models are introduced which predict ratios of mean levels of genetic divergence in species-rich versus species-poor phylads under two competing assumptions: (1) genetic differentiation is a function of time, unrelated to the number of cladogenetic events and (2) genetic differentiation is proportional to the number of speciation events in the group. The models are simple, general, and biologically real, but not precise. They lead to qualitatively distinct predictions about levels of genetic divergence depending upon the relationship between rates of speciation and amount of genetic change. When genetic distance between species is a function of time, mean genetic distances in speciose and depauperate phylads of equal evolutionary age are very similar. On the contrary, when genetic distance is a function of the number of speciations in the history of a phylad, the ratio of mean genetic distances separating species in speciose versus depauperate phylads is greater than one, and increases rapidly as the frequency of speciations in one group relative to the other increases. The models may be tested with data from natural populations to assess (1) possible correlations between rates of anagenesis and cladogenesis and (2) the amount of genetic differentiation accompanying the speciation process. The data collected in electrophoretic surveys and other kinds of studies can be used to test the predictions of the models. For this purpose genetic distances need to be measured in speciose and depauperate phylads of equal evolutionary age. The limited information presently available agrees better with the model predicting that genetic change is primarily a function of time, and is not correlated with rates of speciation. Further testing of the models is, however, required before firm conclusions can be drawn.

Conservation of the Threatened Species, Pulsatilla vulgaris Mill. (Pasqueflower), is Aided by Reproductive System and Polyploidy

2019 ◽  
Vol 110 (5) ◽  
pp. 618-628 ◽  
Author(s):  
Roberta Gargiulo ◽  
Gemma Worswick ◽  
Corinne Arnold ◽  
Lindsay J Pike ◽  
Robyn S Cowan ◽  
...  
Keyword(s):  
Genetic Variation ◽  
Allelic Variation ◽  
Natural Populations ◽  
Wild Populations ◽  
Multiple Sources ◽  
Demographic Trends ◽  
Multiple Allele ◽  
Population Loss ◽  
Nuclear Microsatellite ◽  
Source Populations

AbstractPopulation loss due to habitat disturbance is a major concern in biodiversity conservation. Here we investigate the genetic causes of the demographic decline observed in English populations of Pulsatilla vulgaris and the consequences for conservation. Using 10 nuclear microsatellite markers, we compare genetic variation in wild populations with restored and seed-regenerated populations (674 samples). Emergence of genetic structure and loss of allelic variation in natural populations are not as evident as expected from demographic trends. Restored populations show genetic variation comparable to their source populations and, in general, to the wild ones. Genetic homogeneity is observed in regeneration trials, although some alleles not captured in source populations are detected. We infer that polyploidy, longevity, and clonal reproduction have provided P. vulgaris with the standing genetic variation necessary to make the species resilient to the effects of demographic decline, suggesting that the use of multiple sources for reintroduction may be beneficial to mimic natural gene flow and the availability of multiple allele copies typical of polyploid species.

Assessment of temporal genetic variability of two epibenthic amphipod species in an eastern Australian estuarine environment and their suitability as biological monitors

2014 ◽  
Vol 62 (3) ◽  
pp. 206
Author(s):  
Pann Pann Chung ◽  
Ida Chu ◽  
J. William O. Ballard
Keyword(s):  
Genetic Variation ◽  
Genetic Variability ◽  
Environmental Monitoring ◽  
Organic Contaminants ◽  
Population Studies ◽  
Temporal Trends ◽  
Natural Populations ◽  
Cytochromec Oxidase ◽  
Basic Research ◽  
Amphipod Species

Population studies often assume temporally stable and consistent patterns of genetic variability. Violations of this assumption can lead to misrepresentation of the amount and patterns of genetic variability in natural populations, which can be problematic in basic research and environmental monitoring studies that are designed to detect environmental perturbation. We collected two endemic species of amphipods, Melita plumulosa and Melita matilda, in a major eastern Australian waterway between November 2009 and October 2011, and assessed genetic variation at the mitochondrial cytochromec oxidase subunitI locus. Overall, M. plumulosa was found to be more genetically variable than M. matilda. No distinct temporal trends in levels and patterns of genetic variation were identified in either species. These findings, combined with the published results demonstrating that M. plumulosa has greater sensitivity to a range of sediment-bound metals and organic contaminants, suggests it to be an informative species for environmental monitoring purposes.

scholarly journals Genetic polymorphism among natural populations of Anacardium humile A. ST-HIL

2020 ◽  
Vol 42 (1) ◽  
Author(s):  
Silvia Correa Santos ◽  
Raquel dos Santos Carvalho ◽  
Livia Maria Chamma Davide
Keyword(s):  
Genetic Diversity ◽  
Genetic Polymorphism ◽  
Genetic Variability ◽  
Genetic Divergence ◽  
Genomic Dna ◽  
Reproductive Strategies ◽  
Rapd Markers ◽  
Phenotypic Diversity ◽  
Diversity Index ◽  
Natural Populations

Abstract The genus Anacardium presents nine species, of these, three have sub-bush size, common in the Cerrado of the Center-West of Brazil. The objective of this work was to evaluate the genetic variability of the species, collected in eleven provenances, using RAPD markers. Genomic DNA from 122 accessions was extracted and amplified with 25 decamer primers. The results indicated polymorphism, ranging from 77.71% to 96.18%. The distribution of genetic diversity among and within populations shows that 27.14% of the variability is found between populations and 37.44% within the populations, suggesting the existence of genetic variability that may be related to the reproductive strategies adopted by the species throughout its evolution. The index of variation within the provenances (93.36%) was higher than the index found among populations (6.64%). Molecular analysis indicated that there is genetic divergence between and within the studied populations of Anacardium humile A. St. - Hill. The origin of Itajá-GO presented the highest genetic diversity, presenting the highest values of genetic diversity index, phenotypic diversity and higher percentage of polymorphic loci.

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