Genetic differentiation among various populations of the diamondback moth, Plutella xylostella Lepidoptera Yponomeutidae

2006 ◽  
Vol 96 (2) ◽  
pp. 137-144 ◽  
Author(s):  
A. Pichon ◽  
L. Arvanitakis ◽  
O. Roux ◽  
A.A. Kirk ◽  
C. Alauzet ◽  
...  
Keyword(s):  
South Africa ◽  
New York ◽  
Genetic Variation ◽  
Genetic Differentiation ◽  
Plutella Xylostella ◽  
Diamondback Moth ◽  
The Philippines ◽  
Fixation Index ◽  
Geographical Distance ◽  
Hardy Weinberg Equilibrium

AbstractGenetic variation among 14 populations of Plutella xylostella (Linnaeus) from USA (Geneva, New York), Brazil (Brasilia), Japan (Okayama), The Philippines (Caragan de Oyo), Uzbekistan (Tashkent), France (Montpellier), Benin (Cotonou), South Africa (Johannesburg), Réunion Island (Montvert), and five localities in Australia (Adelaide, Brisbane, Mareeba, Melbourne, Sydney) were assessed by analysis of allozyme frequencies at seven polymorphic loci. Most of the populations were not in Hardy–Weinberg equilibrium and had a deficit in heterozygotes. The global differentiation among populations was estimated by the fixation index (Fst) at 0.103 for the 14 populations and at 0.047 when populations from Australia and Japan, which differed most and had a strong genetic structure, were excluded from the analysis. By contrast, the populations from Benin (West Africa) and Brazil (South America) were very similar to each other. Genetic differentiation among the populations was not correlated with geographical distance.

scholarly journals Population Structure of Phytophthora cinnamomi in South Africa

1997 ◽  
Vol 87 (8) ◽  
pp. 822-827 ◽  
Author(s):  
C. Linde ◽  
A. Drenth ◽  
G. H. J. Kemp ◽  
M. J. Wingfield ◽  
S. L. von Broembsen
Keyword(s):  
South Africa ◽  
Genetic Distance ◽  
South African ◽  
Mating Type ◽  
Phytophthora Cinnamomi ◽  
Regional Distribution ◽  
Specific Pattern ◽  
Fixation Index ◽  
The South ◽  
Hardy Weinberg Equilibrium

Phytophthora cinnamomi isolates collected from 1977 to 1986 and 1991 to 1993 in two regions in South Africa were analyzed using isozymes. A total of 135 isolates was analyzed for 14 enzymes representing 20 putative loci, of which four were polymorphic. This led to the identification of nine different multilocus isozyme genotypes. Both mating types of P. cinnamomi occurred commonly in the Cape region, whereas, predominantly, the A2 mating type occurred in the Mpumalanga region of South Africa. A2 mating type isolates could be resolved into seven multilocus isozyme genotypes, compared with only two multilocus isozyme genotypes for the A1 mating type isolates. Low levels of gene (0.115) and genotypic (2.4%) diversity and a low number of alleles per locus (1.43) were observed for the South African P. cinnamomi population. The genetic distance between the Cape and Mpumalanga P. cinnamomi populations was relatively low (Dm = 0.165), and no specific pattern in regional distribution of multilocus isozyme genotypes could be observed. The genetic distance between the “old” (isolated between 1977 and 1986) and “new” (isolated between 1991 and 1993) P. cinnamomi populations from the Cape was low (Dm = 0.164), indicating a stable population over time. Three of the nine multilocus isozyme genotypes were specific to the “old” population, and only one multilocus isozyme genotype was specific to the “new” population. Significant differences in allele frequencies, a high genetic distance (Dm = 0.581) between the Cape A1 and A2 mating type isolates, significant deviations from Hardy-Weinberg equilibrium, a low overall level of heterozygosity, and a high fixation index (0.71) all indicate that sexual reproduction occurs rarely, if at all, in the South African P. cinnamomi population.

Integrative Model for Binding of Bacillus thuringiensis Toxins in Susceptible and Resistant Larvae of the Diamondback Moth (Plutella xylostella)

1999 ◽  
Vol 65 (4) ◽  
pp. 1413-1419 ◽  
Author(s):  
Victoria Ballester ◽  
Francisco Granero ◽  
Bruce E. Tabashnik ◽  
Thomas Malvar ◽  
Juan Ferré
Keyword(s):  
Bacillus Thuringiensis ◽  
Plutella Xylostella ◽  
Binding Sites ◽  
Diamondback Moth ◽  
The Philippines ◽  
Competitive Binding ◽  
Single Mutation ◽  
Crystal Proteins ◽  
Mechanism Of Resistance ◽  
Resistant Strains

ABSTRACT Insecticidal crystal proteins from Bacillus thuringiensis in sprays and transgenic crops are extremely useful for environmentally sound pest management, but their long-term efficacy is threatened by evolution of resistance by target pests. The diamondback moth (Plutella xylostella) is the first insect to evolve resistance to B. thuringiensis in open-field populations. The only known mechanism of resistance to B. thuringiensis in the diamondback moth is reduced binding of toxin to midgut binding sites. In the present work we analyzed competitive binding of B. thuringiensis toxins Cry1Aa, Cry1Ab, Cry1Ac, and Cry1F to brush border membrane vesicles from larval midguts in a susceptible strain and in resistant strains from the Philippines, Hawaii, and Pennsylvania. Based on the results, we propose a model for binding of B. thuringiensis crystal proteins in susceptible larvae with two binding sites for Cry1Aa, one of which is shared with Cry1Ab, Cry1Ac, and Cry1F. Our results show that the common binding site is altered in each of the three resistant strains. In the strain from the Philippines, the alteration reduced binding of Cry1Ab but did not affect binding of the other crystal proteins. In the resistant strains from Hawaii and Pennsylvania, the alteration affected binding of Cry1Aa, Cry1Ab, Cry1Ac, and Cry1F. Previously reported evidence that a single mutation can confer resistance to Cry1Ab, Cry1Ac, and Cry1F corresponds to expectations based on the binding model. However, the following two other observations do not: the mutation in the Philippines strain affected binding of only Cry1Ab, and one mutation was sufficient for resistance to Cry1Aa. The imperfect correspondence between the model and observations suggests that reduced binding is not the only mechanism of resistance in the diamondback moth and that some, but not all, patterns of resistance and cross-resistance can be predicted correctly from the results of competitive binding analyses of susceptible strains.

Genetic variation within and relationships among five subpopulations of Slovak Thoroughbred

2004 ◽  
Vol 52 (3) ◽  
pp. 259-265
Author(s):  
Daniela Šátková-Jakabová ◽  
J. Trandžík ◽  
Ľudmila Hudecová-Kvasňáková ◽  
Erika Hegedüšová-Zetochová ◽  
A. Bugarský ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Genetic Variation ◽  
Genetic Differentiation ◽  
International Society ◽  
Microsatellite Loci ◽  
Genetic Relationships ◽  
Allele Frequencies ◽  
Weinberg Equilibrium ◽  
Hardy Weinberg Equilibrium

Genetic variation at six microsatellite loci was analysed for five Thoroughbred subpopulations to determine the magnitude of genetic differentiation and the genetic relationships among the subpopulations. Significant deviations from Hardy-Weinberg equilibrium were shown for a number of locus-population combinations, with all subpopulations. The genetic diversities and relationships of five Thoroughbred subpopulations were evaluated using six microsatellites recommended by the International Society of Animal Genetics (ISAG). The allele frequencies, the effective numbers of alleles, and the observed and expected heterozygosities were calculated. POPGENE v. 1.31 (Yeh et al., 1997) was used to test for deviations from the Hardy-Weinberg (H-W) equilibrium and to assign FIS estimates (Weir, 1990). The utility of microsatellites for evaluating genetic diversity of horses is discussed.

scholarly journals GENETIC VARIATION IN INDIGENOUS TURKEY POPULATIONS IN SOUTH WEST NIGERIA

2017 ◽  
Vol 7 (2) ◽  
pp. 1021-1029
Author(s):  
Fatai R. B ◽  
Akinyemi M.O ◽  
Osaiyuwu O. H
Keyword(s):  
Genetic Variation ◽  
Genetic Distance ◽  
Conservation Strategies ◽  
Fixation Index ◽  
Genetic Integrity ◽  
Red Cell ◽  
Protein Markers ◽  
Cellulose Acetate Electrophoresis ◽  
South West ◽  
Hardy Weinberg Equilibrium

The study was carried out to assess the genetic variation in indigenous turkey populations in South West Nigeria using seven protein markers: Hemoglobin (Hb), Albumin (Alb), Transferin (Tf), Esterase-1 (Es-1), Alkaline phosphatase (ALP), Carbonic anhydrase (CA), and Esterase-3 (Es-3).. A total of 97 turkey birds from Ibadan, Ijebu Ode and Akure were purposively sampled. Separation of plasma and red cell proteins were determined on cellulose acetate electrophoresis to estimate the genetic variability within and among the populations. The degree of heterozygosity, deviation from Hardy-Weinbergs Equilibrum (HWE), FIS, and FST values were estimated. From a total of 7 loci analyzed, six were found to be polymorphic in all the populations sampled while Es-1 was monomorphic. Two codominant alleles which controlled three different genotypes were observed at each polymorphic loci. Deviations from Hardy Weinberg equilibrium and a deficiency of heterozygotes were observed in all the populations. Average heterozygosities ranged between 0.13 and 0.20, heterozygote deficit FIT was estimated at 0.5784 while within breed deficit as evaluated by FIS ranged from 0.38 to 0.56. The fixation index FST revealed that genetic diversity within the studied population was moderately differentiated. Genetic distance among the populations quantified through calculation of Nei genetic distance ranged from 0.037 - 0.109. The result obtained may be used as an initial guide in defining objectives for future investigations of genetic integrity and developing conservation strategies for Nigeria indigenous turkeys.

Plutella xylostella (diamondback moth).

2021 ◽  
Author(s):  
Rana M. Sarfraz
Keyword(s):  
South Africa ◽  
Invasive Species ◽  
Bacillus Thuringiensis ◽  
Plutella Xylostella ◽  
Global Economy ◽  
Insect Pests ◽  
Diamondback Moth ◽  
Immature Stages ◽  
Plant Parts ◽  
The World

Abstract The diamondback moth (DBM) is one of the most studied insect pests in the world, yet it is among the 'leaders' of the most difficult pests to control. It was the first crop insect reported to develop resistance to microbial Bacillus thuringiensis insecticides, and has shown resistance to almost every insecticide, including the most recent groups such as diamide. DBM is a highly invasive species. It may have its origin in Europe, South Africa or East Asia, but is now present wherever its cruciferous hosts exist and is considered to be the most universally distributed Lepidoptera. It is highly migratory and wind-borne adults can travel long distances to invade crops in other regions, countries and continents. Immature stages also hitchhike on plant parts and can establish in new areas. DBM costs the global economy an estimated US$4 -5 billion annually, but its impacts on local biodiversity and habitats in exotic ranges are unknown.

Genetic structure analysis of populations of the soybean cyst nematode, Heterodera glycines, from north China

Nematology ◽  
2015 ◽  
Vol 17 (5) ◽  
pp. 591-600 ◽  
Author(s):  
Hui-Min Wang ◽  
Hong-hai Zhao ◽  
Dong Chu
Keyword(s):  
Genetic Differentiation ◽  
Soybean Cyst Nematode ◽  
Host Plants ◽  
North China ◽  
Heterodera Glycines ◽  
Cyst Nematode ◽  
Genetic Bottleneck ◽  
Geographical Distance ◽  
Rehmannia Glutinosa ◽  
Hardy Weinberg Equilibrium

To elucidate the genetic differentiation of the host populations ofHeterodera glycines, 348 individuals from 13 populations of three host plants (Nicotiana tabacum,Glycine maxandRehmannia glutinosa) in north China were genotyped using eight microsatellite loci. A significant departure from Hardy-Weinberg equilibrium (Fis) was found in all populations. BOTTLENECK results showed that only three populations (ZT, CR, and MR) may have experienced a genetic bottleneck. The pairwiseFSTvalues among the three host populations ranged from 0.0503 to 0.2867. There was no significant relationship between the genetic distance and geographical distance. STRUCTURE analyses suggest thatR. glutinosamight have important influence on the genetic differentiation ofH. glycinesin north China. Our study demonstrates thatH. glycinesis an inbred species that is highly genetic differentiated.

scholarly journals Genetic differentiation and diversity of Callosobruchus chinensis collections from China

2015 ◽  
Vol 106 (1) ◽  
pp. 124-134 ◽  
Author(s):  
C.X. Duan ◽  
W.C. Li ◽  
Z.D. Zhu ◽  
D.D. Li ◽  
S.L. Sun ◽  
...  
Keyword(s):  
Genetic Variation ◽  
Gene Flow ◽  
Genetic Differentiation ◽  
Genetic Distances ◽  
Fixation Index ◽  
Group Method ◽  
Callosobruchus Chinensis ◽  
Chain Reactions ◽  
Information Index ◽  
Geographic Populations

AbstractCallosobruchus chinensis (Linnaeus) is one of the most destructive pests of leguminous seeds. Genetic differentiation and diversity analysis of 345 C. chinensis individuals from 23 geographic populations using 20 polymorphic simple sequence repeats revealed a total of 149 alleles with an average of 7.45 alleles per locus. The average Shannon's information index was 1.015. The gene flow and genetic differentiation rate values at the 20 loci ranged from 0.201 to 1.841 and 11.0–47.2%, with averages of 0.849 and 24.4%, respectively. In the 23 geographic populations, the effective number of alleles and observed heterozygosity ranged from 1.441 to 2.218 and 0.191–0.410, respectively. Shannon's information index ranged from 0.357 to 0.949, with the highest value in Hohhot and the lowest in Rudong. In all comparisons, the fixation index (FST) values ranged from 0.049 to 0.441 with a total FST value of 0.254 among the 23 C. chinensis populations, indicating a moderate level of genetic differentiation and gene flow among these populations. Analysis of molecular variance revealed that the genetic variation within populations accounted for 76.7% of the total genetic variation. The genetic similarity values between populations varied from 0.617 to 0.969, whereas genetic distances varied from 0.032 to 0.483. Using unweighted pair-group method using arithmetical averages cluster analysis, the 23 geographic collections were classified into four distinct genetic groups but most of them were clustered into a single group. The pattern of the three concentrated groups from polymerase chain reactions analysis showed a somewhat different result with cluster.

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